Conservation – Page 17 – Shark Research & Conservation Program (SRC)

The imperiled fish fauna in the Nicaragua Canal Zone

April 10, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By Nicole Suren, SRC intern

Plans for a new canal through the isthmus of Nicaragua have just been approved by the Nicaraguan government with little to no restrictions on what preexisting waterways can be used as part of this potential new shipping route. The currently proposed route was planned based on economic and technical considerations, but ecological concerns were not factored into the planning, leading to a variety of potential ecological problems due to the construction of the canal. These ecological detriments include overexploitation of the environment, increased water pollution, water flow modification, destruction or degradation of habitat, and the establishment and spread of non-native species. The currently proposed route is of special concern because it not only passes through Lake Nicaragua, a freshwater ecosystem of very high socioeconomic importance, but also because it connects two currently isolated drainage basins, the San Juan drainage basin and the Punta Gorda drainage basin.

Proposed route (solid line) and alternative routes (dashed lines) of the Nicaragua Canal. The 3 drainage basins involved are San Juan (red), Punta Gorda (blue), and Escondido (yellow). Fish-sampling locations are marked with open diamonds. (Härer et al. 2016)

This study was conducted in order to establish a baseline of biodiversity in the two potentially affected drainage basins, as well as the surrounding basins, so that changes in biodiversity due to the construction of the new canal can be accurately measured and compared against previous levels. The researchers measured biodiversity by taking surveys of the fish in each ecosystem in question with nets, and then sampling two species each from three families of fish that are common in the area. These samples were then used in a DNA analysis, where common sequences of DNA from each species were analyzed for differences. In general, the more similar the DNA sequences, the more closely connected two populations are, and the less similar the DNA sequences, the less closely connected the populations are. Based on the DNA analysis, “populations within the same basin showed almost no genetic differentiation, whereas comparisons across basins exhibited higher differentiation.” This means that populations of fish within the same drainage basin are very similar to each other, while they are quite different from fish in other, unconnected drainage basins. They also found that Punta Gorda and San Juan have 27 species in common, but they also have 24 and 31 species, respectively, that only occur in one basin.

Diagrams showing connectivity between basins (A-C) and within different locations in the San Juan drainage basin (D-F). The sizes of the circles are proportional to the sample sizes, and the proximity of the circles to each other represent how closely connected they are genetically. (Härer et al. 2016)

Measures of biodiversity are important because they can be a direct indicator of how healthy an ecosystem is. In other words, a diverse ecosystem is a healthy ecosystem. Since the San Juan and Punta Gorda ecosystems contain populations that are so distinct from one another (which is one of the ways biodiversity is defined), the proposed connection between the two is potentially detrimental to the health of those environments because the physical barriers maintaining their diversity would be removed, thereby reducing their diversity and health. Because of these effects, the authors strongly recommend that the precautionary principle be used, and that a more ecologically sound route for the canal be chosen before starting construction.

Works Cited
Andreas Härer, Julián Torres-Dowdall, Axel Meyer. “The Imperiled Fish Fauna in the Nicaragua Canal Zone.” Conservation Biology, vol. 00, no. 0, 2016, pp. 1-10, doi:DOI: 10.1111/cobi.12768

Novel use of epidemiological models to control the spread of unwanted behaviors in marine mammals

April 7, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By Cameron Perry, SRC intern

Animal behavior is often learned or passed down through social interactions with other individuals. However, sometimes these socially transmitted behaviors increase exploitation of human resources, which may threaten human safety and economic livelihood (Schakner et al., 2016). Schakner et al. (2016) examined a case study where California sea lions (Zalophus californianus) discovered salmonids that had migrated up the Columbia River to the fish ladders located at the Bonneville Dam. Sea lions began foraging at the dam and increased the mortality of the Columbia River’s salmon and steelhead runs, 13 of which are listed under the Endangered Species Act (Schakner et al., 2016). The mouth of the Columbia River is home to tens of thousands migratory male California sea lions, however, the number of individuals foraging at the Bonneville dam began to sharply increase in 2002. This rapid increase in foraging was attributed to social learning and, in order to protect the endangered salmonids at the Dam, a culling program was established in 2008.

Study area for the case study which shows the Bonneville Dam and the East Mooring Basin where the males aggregate [Schakner et al., 2016]

Social transmission of behaviors often mimic spread of diseases in a population. Schakner et al. (2016) aimed to use models from disease ecology to estimate the social transmissibility of dam-foraging behavior, explain how social transmission can be modeled similarly to diseases and to finally examine how effective and whether culling was necessary.

A California sea lion (Zalophus californianus) goes for a swim [Wikipedia Commons]

The benefits of early intervention are well known in infectious disease ecology and the social transmission of dam-foraging behavior in Californian sea lions supported this claim. The results showed that an earlier start to culling would have led to less overall foragers (Schakner et al., 2016). Similarly, if culling started prior to 2005, then fewer individuals would have to be removed than the current numbers. These results together mean that an immediate implementation of a culling program during the 2002 period of sharp increase in foraging behavior could have reduced the negative extent of social transmission and recruitment to the Bonneville Dam (Schakner et al., 2016). This also highlights the need for early culling efforts from a conservation and management aspect to minimize the total number of animals removed.

The authors hope that the Bonneville Dam case study could serve as an example what should be done in similar situations. They provided a novel synthesis of disease ecology models in social transmission and spread of behaviors in wildlife. Animal behaviors can rapidly spread through a population like an infectious disease. Social transmission of behaviors, like infectious diseases, can be managed through early intervention to reduce their spread and reach through a population.

Works cited
Schakner, Zachary A, Michael G Buhnerkempe, Mathew J Tennis, Robert J Stansell, Bjorn K van der Leeuw, James O Lloyd-Smith, and Daniel T Blumstein. 2016. “Epidemiological models to control the spread of information in marine mammals.” Proc. R. Soc. B.

Coral Recruitment Shifts due to Sensitivity to Community Succession

April 3, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By Patricia Albano, SRC intern

Environmental disturbances such as natural disasters, anthropogenic effects, and weather pattern changes have a significant impact on ecosystems. Following such disturbances, communities must adapt and rebuild through succession where they evolve to respond to changes. In this study, researchers Christopher Doropoulous, George Roff, Mart-Simone Visser, and Peter Mumby of the University of Queensland studied the positive and negative interactions that impact community succession in the wake of a disturbance and how these interactions differ along environmental gradients.

Figure 1. Soft Corals Found on Palau Reef Caption: These are examples of the soft corals (Nephtheidae) that inhabit reefs in Palau. These corals are important for the structure and function of the reefs. Source: Wikimedia Commons

Figure 1. Soft Corals Found on Palau Reef
These are examples of the soft corals (Nephtheidae) that inhabit reefs in Palau. These corals are important for the structure and function of the reefs.
Source: Wikimedia Commons

Succession in ecosystems usually follows 2 models: facilitation and inhibition (Connel and Slayter 1977). Facilitating organisms “set the stage” for environmental modifications, making the habitat more accommodating for the later-successional species. Inhibiting organisms are early arrivers that reserve space in the habitat for themselves and prevent the invasion of later-successional species (Connel and Slayter 1977). All species interaction includes two components: negative (competition, predation, inhibition) and positive (facilitation) (Paine1980). These two interaction types allowed the researchers to classify the changes they saw in the coral reef ecosystem study sites. This series of experiments investigates how early succession affects coral reef recovery after 2 subsequent typhoons in the island of Palau in the Western Pacific (Figure1) These 2 typhoons (occurring in December 2012 and November 2013) occurred after no typhoon disturbances for over 70 years. This study site was used to explore how the changes in species interactions after a disturbance affect succession in benthic communities with different environmental gradients and how these successional changes affect coral recruitment and recovery after a disturbance (Doropoulos et al. 2016).

The researchers analyzed the eastern barrier reef of the island that had significantly reduced abundances of juvenile corals. Six sites were chosen within to different wave environments: 3 at reefs with lower wave exposure and 3 at reefs with higher wave exposure (Figure 2). Variables accounted for include: grazing potential of herbivorous fish on available grazeable substrate and percent cover of algae groups in the ecosystems.

Figure 2: Six Reefs of the Study Site in Palau Caption: This map indicates where the 6 reefs used in the study are located along the Palau coastline. The pictures indicate differences in coral recruitment between caged (shielded from herbivorous fish) and uncaged (open to grazing) portions of the reef. Source: Doropoulous et al. 2016

Figure 2: Six Reefs of the Study Site in Palau
This map indicates where the 6 reefs used in the study are located along the Palau coastline. The pictures indicate differences in coral recruitment between caged (shielded from herbivorous fish) and uncaged (open to grazing) portions of the reef.
Source: Doropoulous et al. 2016

The researchers found that 3 patterns in environmental drivers influenced the ecosystem. First, a 70% reduction in fish grazing potential was found at the sites that had loss of the majority of live coral cover after the typhoons. Second, shifts in dominance from coral to microalgae occurred at 3 sites with medium wave exposure. Last, microalgae was more abundant in microhabitat crevice areas within both the medium and low wave exposure sites. Coral recruitment was also higher in these crevice areas within the reefs. The researchers came to the conclusion that when herbivorous fish are excluded from reef habitats, a gradual shit towards an algae dominated system occurred at both medium and low wave exposure locations. The results collectively showed that differences in interaction strengths along environmental gradients can lead to changes in the early succession of benthic life that can lead to the inhibition of system recovery after a disturbance such as a typhoon. This experiment revealed important information on how ecosystems recover after disturbances. With this knowledge, nations and conservation organizations can effectively manage their reef ecosystems following a disturbance such as a natural disaster or a weather change. This study also reveals how important it is for healthy reefs to exist in order for ecosystems to continue thriving and support a vast array of life.

Works cited:

Paine, R. T. 1980. Food webs: linkage, interaction strength and community infrastructure. The Journal of Animal Ecology 49: 667-685.

Connell, J. H., and R. O. Slatyer. 1977. Mechanisms of succession in natural communities and their role in community stability and organization. American naturalist:1119- 1144.

FAD’s and Food Security in the Pacific Islands

March 31, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By Kevin Reagan, SRC intern

In the countries and territories of the Pacific Islands, the people depend very heavily on fish for food. In Pacific Island countries and territories (PICT’s), 50-90% of the dietary animal protein in coastal communities comes from fish. This is based mostly on small-scale subsistence and commercial fishing for fish mainly associated with coral reefs, as well as some pelagic (open ocean) species (mainly tuna). Consumption of fish here is several times higher than the global average, and tuna is of particular importance and value (Bell et. al 2009).

A map of the Pacific Island region. https://commons.wikimedia.org/wiki/File:Pacific_Culture_Areas.jpg

As human populations grow, the government is encouraged to provide at least 35 kg of fish per person per year, due to the fact the fish is filled with fatty acids, proteins, and vitamins, and the most promising option for food security in the region. The arable, farmable land is scarce, which makes the level of subsistence provided from small farms scarce as well. It is also a better alternative to nutrient-poor imported foods that are beginning to be consumed in the region and can combat the occurrence of non-communicable diseases in the region (Bell et al. 2015).

The main issue currently is that coral reef fish populations cannot keep up with the growing demand for food, and will not yield the necessary 35 kg/person as the population continues to grow. Bell et. al (2015) propose that PICT’s allocate more of the tuna they catch to local food security, and make fish-aggregating devices (FAD’s) a priority. By 2035, it is estimate that tuna with need to account for 25% of the fish required for food security in the region (Bell et al. 2015).

A yellowfin tuna, the most common species of tuna caught in the Pacific Islands. https://commons.wikimedia.org/wiki/File:Al_mcglashan_tuna.jpg

FAD’s are though to be “one of the most practical vehicles for improving local fish access” in PICT’s (Bell et. al 2015), and are installed nearshore in depths of 300-700 meters. Pelagic fish tend to aggregate at and around floating objects for several days, and therefore FAD’s improve access to these fish. They have been shown to improve supply and consumption in rural areas, and cost-benefit analyses of FAD’s show the value of tuna and other pelagic fish exceeds the cost of the FAD by 3-7 times. The catch per unit effort tends to be higher, the average fuel consumption by the fisherman lower, and the returns on investment are anywhere form 80-180%. Preliminary studies in Micronesia and Vanuata indicate that FAD’s can alleviate fishing pressure on coral reef communities as much as 75% by transferring some of the fishing to oceanic fisheries, i.e. pelagic fish (Bell et al. 2015).

Though FAD’s have many benefits, extensive planning, monitoring, and research will be required for them all to be seen. An important aspect of this is participation and a sense of ownership by the local communities; some FAD’s have been sabotaged and vandalized in the past. Investments will need to be made, and are described in detail in the paper (Bell et al. 2015).

A fish-aggregating device (FAD) with mahi mahi schooling underneath. https://www.flickr.com/photos/landlearnnsw/3017619031

The first necessary investment is to identify priority locations for nearshore FAD’s. This is especially important in rural communities but is also important for urban communities. The community then needs to be engaged so that they can realize the full potential of FAD’s and none will be lost due to vandalism. The effectiveness of exclusion zones for industrial fleets must also be assisted; there are concerns that industrial fleets fishing near the boundaries of exclusion zones affect the number of fish that are then contained within the zone. Next, catches around nearshore FAD’s needs to be monitored and the level of improvement of coral reef management initiatives from FAD’s should be evaluated. Finally, the design and placement of the FAD’s must be improved (Bell et al. 2015).

FAD’s provide path to increase tuna and other pelagic fish availability to rural and urban comm. in Pacific Islands. They are a practical way to allow countries to get the small share of the region’s tuna catch they need to have food security, and are also a positive adaptation to climate change and population growth. Exclusion zone expansion needs to be considered as well if it is shown that industrial fleets are catching tuna marked in the exclusion zone (Bell et al. 2015).

Investments need to be made in FADs as part of food security in PICTs. Current FAD numbers not enough, and infrastructure needs to be maintained post-installation. Damaged FAD’s need to be replaced as soon as possible or momentum will be lost in the community. To do this, communities need large stockpiles of spare parts and access to the vessels and personnel necessary to install new FADs. However, current budgets are not large enough. National governments also need to be committed to and have ownership of FAD programs, and potentially use funds from license revenues from distant fishing nations that use their waters (Bell et al. 2015).

Local governments can also enlist the help of industrial fishing companies that currently deploy anchored FAD’s when fishing to assist in the installations of nearshore FAD’s. Each FAD program within PICT’s needs to be adapted to fit the capabilities of each particular island- the points outlined in paper are a blueprint, not a checklist. Overall, FAD’s are one of the few options that can provide food security, especially in rural coastal areas, and should be seriously considered in the coming years (Bell et al. 2015).

Works Cited

Bell, Johann D., et al. “Optimising the use of nearshore fish aggregating devices for food security in the Pacific Islands.” Marine Policy 56 (2015): 98-105.

Bell, Johann D., et al. “Planning the use of fish for food security in the Pacific.” Marine Policy 33.1 (2009): 64-76.

Cleaner fishes and shrimp diversity and a re-evaluation of cleaning symbioses

March 27, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By Shannon Moorhead, SRC Masters Student

If you’ve ever gone diving on a tropical coral reef, you may have noticed some of the fish seemed to be behaving rather strangely: a solitary fish hovering just above the reef while smaller fish pick at its skin and mouth. While this may appear bizarre compared to the other creatures zipping about the reef, this is a common behavior in the animal kingdom known as cleaning symbiosis. Cleaning symbiosis occurs when, after brief communication between the animals involved, a cleaner animal removes harmful materials from a client animal of a different species. This is a mutually beneficial act for both the cleaner and the client: the client is ridded of parasites and dead skin while the cleaner gets an easy meal!

A pair of Hawaiian cleaner wrasse clean a dragon wrasse. [Source: Wikimedia Commons, photo by Brocken Inaglory (https://commons.wikimedia.org/wiki/File:Cleaning_station_konan.jpg)]

Many water-dwelling organisms have been observed cleaning others. Currently, researchers estimate there are about 208 species of marine and freshwater cleaner fish and 51 species of marine cleaner shrimp known to the scientific community. Some of these species are considered “dedicated cleaners”; for these fish and shrimp, cleaning is a major aspect of their lifestyle once they grow past the larval stage. Other, less committed cleaners, are designated as “facultative cleaners”. There are various levels of facultative cleaning. Some facultative cleaners are opportunistic, only partaking in cleaning when the opportunity presents itself. Others may be temporary, acting as cleaners during only a portion of their life cycle.

Interspecific communication between cleaner and client is a key aspect of cleaning symbiosis. Acts of assertion or submission, by client or cleaner or both, are the catalysts that initiate the cleaning process. Often, cleaners will perform a “dance” or touch the client to signal their intention to clean; the willing client then submits and poses itself in a way that indicates its acceptance of the cleaning. While visual cues are important to this process, in some cases tactile stimulation is just as, if not more important. By approaching and touching the client, cleaner fish make it clear that they are not prey items, as prey would not directly approach a potential predator. Cleaning interactions between cleaner shrimp and moray eels, who have poor vision and are primarily nocturnal, are most likely initiated solely by tactile stimulation. Shrimp have been observed touching eels with their antennae and legs, followed by morays submitting and opening their mouth, allowing the shrimp to begin cleaning.

A shrimp cleans inside the mouth of a moray eel.[Source: Wikimedia Commons, photo by Steve Childs (https://commons.wikimedia.org/wiki/File:Moray_Eel_and_Cleaner_Shrimp.jpg)]

Though the cleaning relationship is usually mutually beneficial, sometimes the cleaner or client may take advantage of the other’s trust, referred to as “cheating”. Cheating occurs when the symbiotic relationship is disturbed by one of the partakers. For example, clients have been known to eat their cleaners and cleaners have been reported choosing to eat the mucus or healthy scales of their client fish instead of ectoparasites or dead or diseased tissue. Despite the threat this breach of contract poses to the health of cheated participants, it does not occur often enough to outweigh the benefits of cleaning symbiosis.

Though it is well known that the removal of ectoparasites is beneficial for the health of fishes, the ecological balance maintained by cleaner organisms is poorly understood. Many studies have attempted to quantify loss of reef fish abundance and diversity after the removal of one or multiple species of cleaners from a reef, with varying results. Some studies reported little change in the number of fish, while others reported drastic differences in the number and diversity of fish observed, as well as increases in the number of lesions on remaining fish. The large diversity and abundance of cleaners in marine ecosystems suggest they perform a critical ecological function; the discrepancies among study results make it clear that more research must be done to fully understand the intricacies and significance of cleaning symbiosis.

Works cited

Vaughn DB, Grutter AS, Costello MJ, Hutson KS (2016). Cleaner fishes and shrimp diversity and a re-evaluation of cleaning symbiosis. Fish and Fisheries: 1-19. Doi: 10.1111/faf.12198

Bait worms: a valuable and important fishery with implications for fisheries and conservation management

March 24, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By Brenna Bales, SRC intern

Historically, bait fisheries around the world have been perceived as low-value, and their often limited, local extent makes large-scale management and conservation policy difficult to implement. Watson et. al 2016 explored three ragworm fisheries in the United Kingdom to investigate these claims, based on both evidence gathered scientifically and from an analysis of published literature. The data on polychaete bait fisheries is extremely limited, causing inaccurate estimates of catch amounts and collection efforts. In order to accurately assess the three bait fisheries of focus and other fisheries worldwide, Watson and other researchers assessed the following: retail value of bait species collected, extent of collection efforts both geographically and quantitatively, bait storage methods, and the choice and amount of bait used by angler fisherman on an average fishing trip.

The five most expensive (£/kg) species of marine animals sold on the global fish market are polychaetes (Glycera dibranciata, Diopatra aciculata, Nereis (Alitta) virens, Arenicola defodiens, and Marphysa sanguinea). The values of these bait species were quantified using retail prices of the species online and from data gathered from other literature sources. It was concluded that N. virens landings alone in the UK annually are worth approximately £52 million. Globally, this number is around £5.8 billion, with 121,000 tonnes of N. virens being landed worldwide. This demonstrates the high value of polychaete bait, contrary to popular opinion.

Nereis (Alitta) virens, commonly known as a sand worm, are a popular polychaete worm collected for bait purposes in UK tidal fisheries. (source: https://commons.wikimedia.org/wiki/File%3ANereis_virens_und_Nereis_diversicolor.jpg)

The three UK sites surveyed were Fareham Creek, Portsmouth Harbour; Dell Quay, Chichester Harbour; and Pagham Harbour. They were monitored over a period from August to September 2011, using remote closed circuit television recordings. The time for each digger on-site was recorded, and based on the number of times they placed a worm in their collection bucket, the biomass (mass of live worms) collected was estimated. The mean removal rate per bait collector per hour was 228 ± 64 worms. This large amount of collection can lead to things like environmental disturbance (trampling), over-exploitation of collection species, and the depletion of food resources for bird species that consume these worms.

This Japanese coastal bird feeds off a small ragworm, species that are globally collected as bait. When too many worms are removed by collectors, it can have serious consequences for the animals that rely on them for food. (source: https://commons.wikimedia.org/wiki/File%3ACharadrius_mongolus_stegmanni_eating_ragworm.JPG)

An investigation as to how long certain species could be kept fresh before being used as bait on fishing trips was also conducted. The amount of time that N. virens could be maintained as viable bait was at the least 2 weeks. Given the average amount of N. virens used on angling trips per week was 0.33 kilograms, that amount of bait could be collected in only 28 minutes during a tidal cycle, based on the mean removal rate per bait collector per hour.

In conclusion, Watson et. al. proved that there needs to be a re-examination of the importance of polychaete bait fisheries worldwide, in order for better conservation initiatives to be launched. Seeing as the majority of these bait fisheries are located in MPAs (marine protected areas), better regulations must be enforced. There are several proposals in the study, such as personal catch limits, surveillance conservation, and stakeholder involvement. Overall, these fisheries are worth a lot more than is currently thought, and the implications of continuing poor management could have serious consequences.

Works Cited

Watson, Gordon J., et al. “Bait worms: a valuable and important fishery with implications for fisheries and conservation management.” Fish and Fisheries (2016).

A novel aspect of goby–shrimp symbiosis: gobies provide droppings in their burrows as vital food for their partner shrimps

March 21, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By SRC intern, Andriana Fragola

The goby A. japonica and shrimp A. bellulus symbiosis are a perfect example of a mutualistic relationship between two marine animals. The goby lives in the shrimp’s burrow, which lends it shelter, and the goby warns the shrimp if there is a predatory threat nearby (Kohda et al. 2017). It has been hypothesized that the shrimp actually eats the goby’s droppings as its primary food source (Kohda et al. 2017). Kohda and colleagues conducted a laboratory experiment to replicate this relationship, and examine if this feeding behavior is actually occurring.

Field studies were conducted to examine the goby and shrimp interactive behavior. Between the shrimps, A. bellulus and the gobies A. japonica it was observed that the shrimps were not foraging much outside of their burrow, and the gobies were never really observed defecating outside of their burrow (Kohda et al. 2017). Most burrowing organisms do not defecate inside of their burrows – likely to be an act to keep it cleaner (Kohda et al. 2017). If the shrimp is using the goby’s droppings as a nutritional supplementation, then it would not be an issue of keeping the burrow clean because the droppings would still be removed via consumption by the shrimp (Kohda et al. 2017). The animals were collected at Morote Beach, Ehime Prefecture, Japan and were then studied in a laboratory setting.

The gobies and shrimps were kept in tanks with the burrow being a vinyl tube with one open side up against the glass wall of the tank for visual observation (Kohda et al. 2017). This experiment took place over a 2 week period. The shrimp were weighed prior to and after the experiment to determine if they had lost weight when they had no access to food other than the goby droppings (Kohda et al. 2017). In treatment 1, in order to make the goby feed inaccessible to the shrimp, it was placed on a suspended board away from the entrances of the burrows (Kohda et al. 2017). This way the goby could reach the food by swimming, but the shrimp could not and had to rely entirely on the goby droppings for nutrition. In treatment 2, the gobies and shrimp were kept in different tanks, and the researchers collected the goby faeces and then placed them up at the top of the shrimp’s burrow (Kohda et al. 2017). The shrimps were noted to come to the entrance and collect the faeces and bring them back down into the burrow and eat them (Kohda et al. 2017). A control tank was set up where the shrimp were isolated from the gobies, and were not fed during the entirety of the experiment (Kohda et al. 2017).

Final observations noted that the gobies stayed very close to the burrow unless they were feeding, and were never observed defecating outside of the burrow (Kohda et al. 2017). The shrimp were never noted to forage outside of the burrow unless they were taking algae off of the rocks near the burrow entrance (Kohda et al. 2017). Between the two treatments, there was not a significant difference between body weight of shrimps prior and after the experiment (Kohda et al. 2017). But there was a significant decrease in shrimp body weight in the control groups where they were isolated from the gobies (Kohda et al. 2017). Meaning that the shrimp were able to maintain a stable body weight with only the goby faeces as food (Kohda et al. 2017).

Understanding behavioral relationships between species is incredibly important for conservation initiatives. Learning that two species heavily rely on each other to thrive is vital in establishing protection for them. In a mutualistic relationship similar to this, both species need to be protected because if one is missing, they cannot perform their usual behaviors, and do not have that resources they typically rely on. For example, the droppings of the goby being a primary food source by the shrimp. This study demonstrated that solely having goby droppings as food is enough to maintain the shrimp’s weight even without other nutritional sources available (Kohda et al. 2017). Therefore the goby is a very beneficial to the shrimp as a partner, and without these mutualistic relationship the shrimp would have a much more limited food supply, and the goby would not have a burrow to reside in.

Works cited
Kohda, M., Yamanouchi, H., Hirata, T., Satoh, S., & Ota, K. (2017). A novel aspect of goby–shrimp symbiosis: gobies provide droppings in their burrows as vital food for their partner shrimps. Marine Biology, 164(1). doi:10.1007/s00227-016-3060-2

Use of local ecological knowledge to investigate endangered baleen whale recovery in the Falkland Islands

January 23, 2017/1 Comment/in Conservation, Ocean News /by a.anstett

By SRC intern, Molly Rickles

In this study, Frans and Auge looked at baleen whale population in the Falkland Islands in the post-whaling era. Due to whaling in the early 1900s, whale populations here have decreased dramatically, but recent observations suggest that their numbers are currently increasing. However, there is a lack of population data, making this study critical.

Methods

The main goal of the research was to understand how well the baleen whale population is doing post-whaling in the Falkland Islands. To do this, the scientists used LEK, or local ecological knowledge. In this method, interviews were conducted with local Falkland residents to determine how often whales are sighted off the coast. The residents were asked to draw pictures on a map of where they saw the whales. Each interview was given a reliability rating based on how confident and detailed the account was. This data was used to supplement the existing International Whaling Committee data from the whaling era. With the combined data, the researchers aimed to look at when the whale sightings were most common and to determine the most common places where the whales were seen.

Results

Over the course of the study, 3,842 whale sightings were recorded and Falkland residents recorded 631 of those observations. Since LEK is not always a reliable method, it was determined that about 70% of the observations recorded using LEK were reliable, and could be used in the study. It was found that in the 1970’s, no whale sightings were recorded because it was right after the whaling era. By the early 2000’s, the number of whale sightings increased 11-fold, showing a population recovery. Out of all of the baleen whale species, sei whales (Balaenoptera borealis) showed the largest increase since the whaling era, and are currently the most abundant whale species in the Falkland Islands. It was also determined that baleen whales are most common during the summer and fall months, based on recorded sightings.

Outcomes

This study was an important step in understanding baleen whale populations and how they have recovered since the whaling era. Using LEK allowed the scientists to get population data even when there was a lack of empirical data, which is a new technique that hasn’t been used regularly in other studies. This new technique allowed the researchers to determine baleen whale populations in the Falkland Islands, which can be used as a reference for the future of whale conservation. This is especially critical now because of the increasing threats to whales, such as increasing economic development in the Falkland Islands. Since the whales have recovered from the whaling era, it is now important to keep the population healthy, and this study provides an important monitoring tool for future conservation efforts.

References

Frans, V.F., & Auge, A. A. (2016). Use of local ecological knowledge to investigate endangered baleen whale recovery in the Falkland Islands. Biological Conservation, 202, 127-137. dio: 10.1016/j.biocon.2016.08.017

Decorating behavior begins immediately after metamorphosis in the decorator crab Oregonia gracilis

January 16, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By Nicolas Lubitz, SRC intern

Invertebrates, animals without a backbone, are the oldest form of animals that exist on our planet. The first fossils of invertebrates date back to 665 million years ago, and are sponges. Since then, they have diversified into a spectacular array of organisms, both marine and terrestrial. From insects, to squids and corals, to jellyfish, their forms and shapes seem to know no limits. Some studies suggest that invertebrates make up 97% of all animal life on the face of the earth. For example, coral reefs provide shelter and structures for other organisms, most invertebrates are prey for higher organisms, but many invertebrates are predators themselves, like squid. With no doubt those creatures are vital to our marine and terrestrial ecosystems, and understanding their biology helps us to ultimately understand how every part of an ecosystem revolves around another part.

Figure 1. Invertebrate diversity (http://www.deepseanews.com/2011/11/octopi-wall-street/)

Because of the fantastic diversity of tasks they perform conserving invertebrate diversity is important to ocean health. Steven R. Hein and Molly W. Jacobs from the University of Washington and Miami University, respectively, have shown that there is even more to consider when looking at marine invertebrates. In their recent paper they looked at the decorator crab Oregonia gracilis (figure 1). Decorator crabs are known to use debris and other organisms such as sponges and algae to cover their outer layer, most likely for camouflage and protection. Just like other invertebrates of the order crustacea (which includes crabs and lobsters) decorator crabs go through different stages in their lives from larvae, to an intermediate phase, the so called megalopa, to a juvenile phase to the final adult stage. Each phase is very different in appearance and behavior. Hein and Jacobs were interested in how those different life stages utilize different habitats and different forms of debris and organisms to decorate themselves and how.

Figure 2. The decorator crab, Oregonia gracilis (http://www.crabs.ru/russia/fam_oregoniidae_oregonia_gracilis.htm)

In order to do so, they collected and bred different life stages of this particular decorator crab species and provided them with different decorating materials and habitats and compared the different stages for preferences. The results are clear: Although the early megalopa phases were found in mostly the same habitat as the juvenile phase, they did not decorate themselves at all. Juveniles, on the other side, utilized free floating organic debris to cover themselves which in turn is very different from adult individuals who use algae, sponges and other organisms. According to the researchers, the different body shapes of megalopae, juveniles, and adults requires all phases to adapt to different niches in order to survive.

When we look back to our idea of conservation we realize that when trying to come up with regulations and protective measurements for such organisms we should understand every single life stage of this particular organisms in order to ensure their conservation and protection. Hein and Jacobs indirectly demonstrated that laying out conservation measurements for just the adult phase appears to be insufficient since the whole life cycle has to be taken into consideration. Here we see that conservation is an integrative field and includes many components that we must look at for conserving our oceans.

Reference

Hein, S.R. & Jacobs, M.W. (2016) Decorating behavior begins immediately after metamorphosis in the decorator crab Oregonia gracilis. Marine Ecology Progress Series, 555, 141–150.

Sea Bird Telomeres

January 9, 2017/0 Comments/in Conservation, Ocean News /by a.anstett

By Dave Lestino, SRC intern
Telomeres are located at the ends of each DNA strand. They can be thought of as the plastic tips of shoelaces, and protect the chromosome from deterioration. Although telomeres can’t measure exact chronological age, they can be used to measure individual quality. Use of telomere length, as a quality marker, is increasing as seen in handful of studies between 2004 and 2015. In most species, it has been observed that telomeres shorten overtime, and length corresponds with survival, life-span and reproductive success. In a study by Young et al. in 2016, telomere lengths were compared to quality markers, such as environmental condition, in the thick-billed murre.

Methods
Young et al. assessed individual quality through parental investment behaviors (trip rate and nest attendance), body condition and physiological stress (baseline corticosterone or CORT). Their samples came from three colonies of thick-billed murre (Uria lomvia), which is a species of long-lived seabird. They sampled 97 individuals from 3 colonies (Bogoslof, St. George and St. Paul) in the Baring Sea, each living under different environmental conditions. The colony on Bogoslof had easy access to nearby food sources, while St. George had access to distant but reliable sources and St. Paul had access to nearby but unreliable food sources. These food sources relate to good, intermediate and poor environmental conditions comparatively.

Young chose this species because murres are known to adjust time budgets as conditions in the environment change, in order to offer consistent levels of parental investment. Thus, telomere length would indicate quality indicators and not age as the underlying driver of telomere length. The authors predicted that longer telomere length would be associated with low baseline CORT, high body condition and high parental investment. They also predicted poor environmental conditions should strengthen the above relationships. Chick rearing murres were captured, weighed, sampled for blood and fitted with Cefas G5 loggers to record time, temperature and depth pressure every 2 seconds. After 3 days the birds were recaptured and skeletal measures were taken. In total 101 birds were captured, but due to some sampling errors the final analysis consisted of 97 individuals.
For telomere length and baseline CORT assays were completed on the blood samples. Parental investment was based on nest attendance and rate of foraging trips. To calculate nest attendance, they looked at what proportion of total time was spent at the colony, measured by a Cefas loggers mounted on the birds, recording temperature and depth. Temperatures reading higher than air or sea indicate incubation, while changes in incubation temperature marked the beginning and end of a foraging trip. Trip rate was then determined by dividing the number of trips by the total deployment time. Response variables (CORT, body condition, trip rate and attendance) were analyzed with linear models in the R environmental statistic program.

Results
The results showed that under good environmental conditions CORT was higher in birds with shorter telomeres. In poor conditions however, this was not strengthened as predicted but instead was reversed. Birds with longer telomeres had higher levels of stress. This implies that under stressful conditions, such as the poor environment at St. Paul, younger birds will be stressed even with high individual quality. Older more experienced birds however can maintain moderate stress levels. Predictions that telomere length could predict parental investment were incorrect. A paper by Elliott et al. in 2015 shows that parental behaviors don’t change with age. Murres have shown to change foraging strategies depending on distance to food sources. The interaction of sex and colony for explaining attendance patterns can be seen in Fig. 3. In conclusion, the authors found that telomere length relates to stress levels with environmental factors acting as important mediators. As habitats around the world decline, these findings can hopefully help in futures studies to determine individual quality of species in degraded areas

References
Young RC, Barger CP, Dorresteijn I, Haussmann MF, Kitaysky AS (2016) Telomere length and environmental conditions predict stress levels but not parental investment in a long-lived seabird. 556, 251–259.