Expanding fisheries management and marine conservation across borders

By Mitchell Rider, SRC master’s student

In 2006, the U.S. Congress reformed the Magnuson-Stevens Fishery Conservation and Management Act (MSA) – an act that directs marine fisheries management – by amending the High Seas Driftnet Fishing Moratorium Protection Act. This new amendment directed Secretary of Commerce to recognize foreign nations identified as participating in the bycatch of protected living marine resources (PLMRs) by including them in a biennial report presented to Congress. The responsibility of identifying participating foreign nations was delegated to NOAA Fisheries. The procedure for identification was delineated as follows: Once participation in bycatch is confirmed, NOAA must consult with the participating nation to inform them about the MRA, define the requirements of meeting positive certification, offer help in meeting that certification, and outline the consequences of receiving negative certification. Positive certification is met when a management plan to regulate bycatch is implemented and yields results comparable to that of the U.S. Negative certification is received when the participating nation fails to do so, and this is met with U.S. sanctions.

Image of a loggerhead turtle escaping a net equipped with a turtle excluder device (TED). [By NOAA – http://www.nmfs.noaa.gov/pr/images/turtles/loggerhead_ted-noaa.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=24936235]

Mexico was the first nation to be recognized for PLMR bycatch and was recognized specifically for the bycatch of an internationally shared PLMR, the North Pacific loggerhead turtle in 2013. In their paper, Senko et al. (2017) illustrates the effects of identifying Mexico for bycatch of the North Pacific loggerhead turtle and potential recommendations for improving management and its implementation.

Loggerheads nest along the coast of Japan, but perform developmental migrations taking them into the North Pacific basin where a proportion of the population recruits into the Gulf of Ulloa along the Pacific coast of Baja California Sur. It is in this location off the coast of Mexico loggerheads are subjected to high rates of bycatch by bottom-set nets targeting commercially important species like halibut. Mexico was identified after the concurrent discovery of >1,000 beached loggerhead carcasses and 88 loggerheads captured in bottom-set nets.

Upon identification, Mexico initially denied the bycatch of loggerheads even though they had agreed to reduce bycatch rates. At this point, the Mexican government disregarded its collaboration with the U.S. to test turtle friendly fishing gear, and instead proposed a plan to establish a protected area for the loggerhead within the Gulf of Ulloa. In response, the U.S. decided, as a compromise, to grant Mexico more time to establish this protected area. Instead, Mexico utilized this time to establish a partial fishing reserve. Since Mexico did not comply with U.S. regulation standards, the U.S. gave Mexico a negative certification. Almost a year later, Mexico established new loggerhead bycatch control measures, which ultimately lead the U.S. to grant a positive certification.

A map of Mexico where the Baja California Sur (BCS) is shaded in with green.[CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=63837]

From this case, Senko et al. proposed policy recommendations to improve the processes of identification and consultation of the new amendment. Because of the Gulf of Ulloa closure and the trade sanctions, thousands of fishermen did not receive an income for one summer. Therefore, the U.S. should consider the potential socioeconomic and political effects that result from these threatened trade sanctions. In addition, there should be a universal form of reporting bycatch data from each country so fewer countries that do report their data are not as dissected as ones that do not do this. Finally, the authors suggested NOAA Fisheries be provided with more resources to create better collaborative relationship with the identified nation. In this case, a better relationship with Mexico may have prevented them from denying allegations initially, thus delaying the process of management implication. If these recommendations are implemented into the identification and consultations processes, the U.S. could avoid creating socioeconomic and political hardships.

Works cited

Senko, J., L. D. Jenkins, and S. H. Peckham. 2017. At loggerheads over international bycatch: Initial effects of a unilaterally imposed bycatch reduction policy. Marine Policy 76:200-209.

Local taboos could help conserve marine fisheries in Tanzania

By Jess Daly, SRC Intern

In developing nations it is often difficult to effectively enforce marine conservation laws because of a lack of staff and funding. With so little government intervention, it may be unclear to what extent the rules are being followed. A 2017 study by Shalli et al. examined how alternative methods of management might be affecting fisheries in Tanzania.

Specifically, the focus of this project was how traditional knowledge and local taboos alter the behavior of local fisherman. Traditional knowledge is wisdom that is passed down through generations, and taboos are a subcategory that includes the belief that certain actions are either too immoral or too sacred to be done in good conscience. The study examined six different Tanzanian fishing communities (4 rural and 2 urban), and used a wide variety of survey methods to gather information, including observation of fishing practices, a questionnaire given to fishers, and interviews with village leaders.

Figure 1

A fisherman goes out with his boat in the waters off of Dar-es-Salaam, Tanzania. [Grant, Milton. “Fishing in Tanzania.” United Nations Photo. 01 May 1991. https://www.flickr.com/photos /un_photo/34848229512]

Those who were given the questionnaire were also asked to provide their ages, genders, education levels, and lengths of residency. Across all of the villages, the majority of fishers were men who were between the ages of 30-40 and had a primary school education or less. However, when asked about local taboos, it was the uneducated elders who were able to provide the most information.

It was discovered that a wide variety of taboos exist within the Tanzanian fishing communities. The first is that certain fish species should not be eaten; reasons given for non-consumption included religious beliefs and fear of toxicity. Specific species and explanations of the taboos varied in the different villages, but all of them discussed dietary restrictions in one way or another. While the trend was present, however, the study found that nearly 50% of respondents did not comply with this taboo. A second class of taboos includes several actions involving the creation and deployment of fishing gear (such as women not touching new nets). These rules were more closely followed, with 44% of respondents claiming that they stringently complied with them, partially because of fear of social backlash. Almost 77% of fishers admitted noncompliance with taboos related to restrictions before or during fishing. More than 97% did not adhere to local taboos that prohibit fishing on certain sacred reefs, and nearly 47% claimed that they fished on certain prohibited days (such as religious holidays).

Figure 2

A graph depicting the levels of compliance to six different “categories” of taboos by different groups of fisherman as either strong, weak, or none. [Shalli et al. https://www.dropbox.com /sh/iyrngyxjy05qhm5/ AACAfkJqi4aOBqumSsEb0cZNa? dl=0&preview=shalli+et+al+2017.pdf]

Many of the local taboos, if they were widely followed, would aid in marine conversation by limiting things like fishing days, target species, fishing in sensitive reef areas, and catch size. While it appears that the majority of taboos are ignored in practice due to growing village populations and an increased demand for fish, it is believed that if local fishermen were educated in how these taboos actually affect population sizes, they would be more likely to observe them. In addition, local conservation laws should be aligned with existing taboos to highlight just how much they could aid in successful fisheries management.

Work Cited

Shalli, Mwanahija Salehe, et all. 2017. The role of local taboos in management of marine fisheries resources in Tanzania. Marine Policy 85: 71-78.

Analysis of a drop chain trawl as a method of bycatch reduction with squid, skates, and flatfish

By Brenna Bales, SRC Intern

It is no secret that bycatch is a huge problem threatening the health of the oceans. Gillnets, longlines, and trawl nets often capture many more unintended species than what is originally sought after. In order to reduce this extremely wasteful practice, it is imperative that new systems and new technologies be created to find a solution. Here, Bayse et al. (2016) tested the viability of drop-chain trawls as a tool to reduce bycatch.

The ground-gear rigged to the trawl net included rubber disks and rollers, designed to prevent the catch of any unintended benthic species.

The ground-gear rigged to the trawl net included rubber disks and rollers, designed to prevent the catch of any unintended benthic species.

Drop-chain groundgear, configured beneath a trawl net for this experiment, was determined to be effective at reducing bycatch in the Nantucket sound squid fishery off of Cape Cod, Massachusetts, USA. Longfin inshore squid (Doryteuthis pealeii) are the intended catch in the surrounding waters, however summer flounder (Paralichthys dentatus) and skates (family Rajidae) are two species that often find their way into the trawls as bycatch. Concerns have been raised throughout the area’s other fisheries that the use of this new system’s heightened foot-ropes will result in a lower catch due to squid escaping underneath the fishing line. However, this system is designed to take advantage of the benthic behaviors of the bycatch species during the trawling process (Ryer, 2008; Winger et al., 2010), without compromising the ability to capture squid.


On the 16th and 17th of June, 2012, four tows were conducted aboard the F/V Atlantic Prince. Underwater video was recorded using an HD GoPro in shallow, clear water during daylight hours. The camera was placed in the trawl at the top of the net, facing forward and slightly down towards the mouth of the trawl. From the recordings, the following events were quantified: entrance into the trawl or escape underneath the fishing line and between drop-chains, contact/impingement between animals and ground gear, swimming behaviors, positions, orientations and time in trawl mouth. These behaviors were subsequently assessed as to whether the capture or escape of the animal resulted.

Hundreds of fish accidentally caught in the net of a shrimp fishery, June 1969. Source: Wikimedia Commons.

Hundreds of fish accidentally caught in the net of a shrimp fishery, June 1969. Source: Wikimedia Commons.


A total of 2,532 individual squid were observed, of which zero escaped. 99.0% of squid were oriented with their mantle in the direction of towing. As for summer flounder, 87 total were observed, however 44 had an unknown capture outcome. Of the 43 whose capture outcome was known, 26 entered the trawl and 17 escaped. 76.7% of the flounder changed direction as they were swimming, subsequently entering the trawl. Last but not least, 197 skates were observed at the mouth of the trawl, of which 175 escaped. 91.8% of all skates were oriented in the same direction as the trawl.


From these results, it was determined that the modified drop-chain trawl, specifically modified to accommodate the behaviors of the bycatch species, was effective in reducing the number of skates caught, but ineffective for reducing summer flounder bycatch. In addition, it did not compromise the ability of the net to catch squid. All in all, this is just one method of bycatch reduction that has proved successful. In combination with several other methods, such as larger trawl mesh sizes, or the use of grids, we can reduce the harmful impact of other commercial fisheries.


Bayse SM, Pol M V, He P (2016) Fish and squid behaviour at the mouth of a drop-chain trawl: Factors contributing to capture or escape. ICES Journal of Marine Science, 73, 1545–1556.

Ryer, C. H. 2008. A review of flatfish behaviour relative to trawls. Fisheries Research, 90: 138–146.

Winger, P. D., Eayrs, S., and Glass, C. W. 2010. Fish behaviour near bottom trawls. In Behaviour of Marine Fishes: Capture Processes and Conservation Challenges, pp. 67–103. Ed. by P. He. Willey-Blackwell, Ames, IA.

Why do Fishers Fish?

By Emily Rose Nelson, SRC Graduate Student

Humans have been fishing for over 40,000 years. Initially, the world’s waters were thought of as a resource with no bounds. However, intensification of fishing pressure over the last 100 years has decimated fish populations, forcing us to realize that the oceans’ resources indeed do have limits. Today, fish make up more than 16 percent of the global human protein intake, whether it is in the form of subsistence fishing in developing countries or extravagant restaurants in wealthy countries. As demand for marine resources continues to grow, pressure on fish populations is also increasing. Governments around the world have started making efforts to slow the decline of ocean resources, but in many cases the success of these initiatives is dependent on compliance of the fishermen. Essentially, conservation efforts are in direct conflict with fisher objectives. For this reason, it is important to understand why a fisher is fishing in the first place – knowledge of fishers’ motivations will help policy makers identify the most effective conservation methods.

Young et al. 2016 set out to answer the question, “Why do fishers fish?” using an ethnographic approach. They conducted semi-structured interviews of experienced male fishermen at two sites, Australia and the Solomon Islands. The interviews gathered information about their general background, fishing methods, motivations for fishing, and feelings upon return from a fishing trip.

The interviews identified an overwhelming split in motivation to fish between the two study sites. 100 percent of fishers in the Solomon Islands were motivated by food and 93 percent were motivated by income. In contrast, 96 percent of the fishers in Australia were motivated by a connection to the environment. Recognizing these differences in incentives can help managers to form the best conservation policy for each region. For example, one could not realistically set in place a no-take marine reserve throughout the Solomon Islands without providing the fishermen and their families with an alternate source of food and income.

Motivations for fishing in Australia (gray bars) and the Solomon Islands (black lines).

Motivations for fishing in Australia (gray bars) and the Solomon Islands (black lines).

Despite the drastic difference in ‘primary reason to fish’ between the Solomon Islands and Australia, interviews revealed that many other drivers were the same. When fishers in the Solomon’s were given a hypothetical situation in which they had secured an alternate income, 100 percent of interviewees indicated that they would still continue to fish whenever possible. This shows that the fishers are getting enjoyment out of their work and indicates the presence of a somewhat recreational mindset. Therefore, if economic conditions were to improve in the area there would likely be a growth in recreational fishing. In Australia, where recreation is the primary reason for fishing, 80 percent of fishers identified food as a secondary incentive. For those people, fishing provides an escape from their stressful day to day lives, with the added bonus of catching a fresh meal for a price much cheaper than what is available at local fish markets.

Young et al. were not only able to identify clear-cut cultural differences in fishing motivations, but also recognize that fishing may provide benefits to individuals and communities that transcend these traditional motivations. In both the Solomon Islands and Australia, mentions of social bonds with fellow fishers and camaraderie were widespread in interviews. Lastly, the interviews revealed that fishing might not be as far off from conservation as some may think. The values identified of many fishers in this study, such as “teach children to appreciate nature” and “foster respect for the environment” are very similar to those of conservationists. As said by an Australian fisher, “fishing provides environmental benefits because we like to protect things that are dear to us.”


Young, A.L., Foale, S., & Bellwood, D.R. (2016) Why do fishers fish? A cross-cultural examination of the motivations for fishing. Marine Policy, 66: 114-123.

Addressing knowledge gaps to utilize best practice management for bottom-trawling fisheries

By Grace Roskar, SRC Intern

Bottom-trawls are a type of fishing gear that can be destructive towards the seabed and its associated organisms. A fishing vessel tows large trawl nets that trap marine animals as they are dragged across the ocean floor. With heavy ropes, chains, or bars, the fishing gear disturbs the seabed while capturing nearly anything in its path. About 20% of fish and shellfish caught globally every year are caught using bottom-trawls, amounting to about sixteen million tons.

A typical bottom trawl. Source: http://commons.wikimedia.org/wiki/File%3ABenthictrawl.jpg

A typical bottom trawl. Source: http://commons.wikimedia.org/wiki/File%3ABenthictrawl.jpg

A meta-analysis by McConnaughey et al., in 2005 has shown that bottom trawling for benthic invertebrates may cause reductions in a decrease in biomass, the diversity of fish, and the body size of fish, among other ecological traits of fish communities. Some fish species use specific habitats for shelter or food, and it may be possible that trawling and dredging impact the productivity of these fish species. This is especially important to examine because wild-capture fisheries provide a substantial amount of food for the growing global population.

This study aimed to identify specific questions about bottom-trawling fisheries that key stakeholders feel need to be scrutinized in order to guide suitable policy and management measures. The research also sought out important gaps in global knowledge that, if taken into consideration, would help the advancement of best practice management for bottom-trawling fisheries, defined as ‘bottom trawling that would achieve sustainable fisheries production while minimizing adverse impacts on the environment’ (Kaiser et al 2015).

First, a group of 52 stakeholders from 11 different countries was selected. Stakeholders were categorized either as research scientists or practitioners, a group that comprised of people from fishing and processing industries, non-governmental organizations, or governmental organizations. The stakeholders composed a comprehensive list of ‘knowledge-needs’, which were then voted on and ranked in terms of priority. The underlying idea was that addressing these knowledge-needs would be necessary to support the development of best practice management. Through a one-day workshop, including discussion sessions and voting, a list of 25 top-priority knowledge-needs were finalized out of the original 108.

This flow diagram shows the methods of prioritizing knowledge-needs into a final list.

This flow diagram shows the methods of prioritizing knowledge-needs into a final list.

Several statistical tests were used to examine how the reasoning behind the rankings varied between practitioners and scientists. The median scores were positively correlated for each knowledge-need, showing high agreement levels between the scientists and practitioners of what was top priority. Knowledge-needs were organized into categories: direct effects, ecosystem and production, operational, and management and indicators. The management and indicators category was the most represented, with six knowledge-needs in the top ten. The highest-ranked knowledge need was ‘What is the extent and distribution of different seabed habitat types?’ Given the wide range of different stakeholders consulted, the agreement between the scientists and practitioners about the importance of this knowledge-need is encouraging. It shows the pressing need to better understand the relationship between bottom-trawling and the different habitat types affected. Furthermore, six other knowledge-needs were related to some extent to improving knowledge of the impacts of interactions between fishing gear and the seabed. The second most highly ranked question asked, ‘What level of trawl fishing impact on other ecosystem services is acceptable such that sustainable seafood production can be maintained?’ This question suggests that the environmental impacts of bottom trawling, such as changes in ecosystem structure and the fish population, need to be evaluated in comparison to the social and economic impacts of trawling.

A list of the top ten knowledge-needs, including what category each was placed in.

A list of the top ten knowledge-needs, including what category each was placed in.

The rest of the knowledge-needs addressed a range of topics, from the need for better understanding of where bottom trawling occurs and how much of it, to evaluating the ability of certain habitats to recover from the effects of trawling. Many knowledge-needs were additive, such that addressing one would help advancement to another. The study successfully identified specific questions that will be collaboratively discussed further to close knowledge gaps in the global fisheries industry. Future research would include continuing to examine collective knowledge and to use discussion to work towards closing knowledge gaps.



Kaiser, M. J., et al. (2015). “Prioritization of knowledge-needs to achieve best practices    for bottom trawling in relation to seabed habitats.” Fish and Fisheries.      doi: 10.1111/faf.12134

McConnaughey, R. A., and Syrjala, S. E. Short-term effects of bottom trawling and a storm event on soft-bottom benthos in the eastern Bering Sea. – ICES Journal of            Marine Science, 71: 2469–2483.

Integration of Indicator Alarm Signals for Ecosystem-Based Fishery Management

By Robert Roemer, SRC Intern

Taking into account different stakeholder’s priorities, while combining ecological, economic, and recreational indicators for managing sustainable fisheries have been a long-standing problem. While not a new issue, these quandaries are only compounded when opinions conflict within each ecological, socioeconomic, and recreational stakeholder class.

A recent study conducted by Duggan et al. 2015 aim to address this problem by utilizing a ‘signal detection” approach, by focusing on shifting issues of multiple indicators usually with inconsistent, conflicting units to a simpler state. In the researchers eyes, simplicity is vital to successfully managing fisheries stocks. By reducing conflicting management approaches and units to just two management options (reduce harvest rate or not reducing the harvest rate), researchers can calculate just one signal, termed the “Response Support Signal” (RSS). The Response Support Signal is derived from the complete range of indicators and opinions then quantifies the level of support to reduce, or not-reduce the harvest rate.

How did the researchers determine the RSS?

First, time series fisheries data was obtained from ICES reports for a total of nine Celtic Sea stocks. Then, 21 indicators were obtained from the literature that covered a variety of metrics like: average weight; discard rate; species evenness; and fuel costs over different time frames. From each indicator, a “status signal” was computed, with each status signal composed of two stages; (1) the indicator or “warning signal” which revealed if each indicator was beyond its threshold, and (2) if adjusting the indicator via a hypothetical change would align with the warning signal (i.e. reducing when indicator is beyond threshold and not reducing when within its threshold). From this, sets of indicator-stock combinations are formed with each having a respective status signal: Hit − (H −), Hit + (H +), Miss (M), and False Alarm (FA). From the frequency of status signals in each indicator, the true positive rate (TPR) and false positive rate (FPR) were calculated by:

TPR= N(H −) / N(H −) +N(M) and FPR= N(FA) / N(H +) + N(FA)

where N(x) denotes the frequency of occurrence of x. The TPR is then plotted against the FPR to determine the degree of alignment between decisions and the indicator values.

Figure 1: ROC plots where each point represents a fish stock time series. The further to the top left corner, the more often management actions were appropriate to indicator signal. Points below the line and right indicate inappropriate responses to indicator signal.

Figure 1: ROC plots where each point represents a fish stock time series. The further to the top left corner, the more often management actions were appropriate to indicator signal. Points below the line and right indicate inappropriate responses to indicator signal.


What has been concluded?

When data is pooled across stock and years, it shows historical management trends to be independent of indicator alarms. A higher occurrence of H + and M rather than H – and FA, indicates a bias of historical management practice to not reduce fishing mortality (64% of years analyzed). However, what is surprising is after investigating all eight stakeholder scenarios, it was found that all support a reduction in fishing mortality from 1980 to present, with special emphasis on the timeframe of 1990-2003.

The authors in this study identified the critical need for fisheries management to be scientifically objective, and have offered a framework that is both practical and effective for assessing a variety of indicators that are integral to the field of fisheries management. The defined RSS values include objective indicator information that harmonizes with stakeholder preferences, a valuable asset to be used for management decisions. One object of note, the authors acknowledge this tool is not necessarily intended to advise mangers to what course of action is best management, but to structure the communication and to facilitate discussion between various stakeholder groups to help achieve best practices.



Duggan, D. E., Farnsworth, K. D., Kraak, S., & Reid, D. G. (2015). Integration of Indicator Alarm Signals for Ecosystem‐Based Fishery Management. Conservation Letters8(6), 414-423.