Bycatch

High Coral Bycatch in Bottom-Set Gillnet Coastal Fisheries Reveals Rich Coral Habitats in Southern Portugal

Dias V, Oliveira F, Boavida J, Serrão EA, Gonçalves JMS, Coelho MAG. High Coral Bycatch in Bottom-Set Gillnet Coastal Fisheries Reveals Rich Coral Habitats in Southern Portugal. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.603438/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1495887_45_Marine_20201201_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Bottom-contact fisheries are unquestionably one of the main threats to the ecological integrity and functioning of deep-sea and circalittoral ecosystems, notably cold-water corals (CWC) and coral gardens. Lessons from the destructive impact of bottom trawling highlight the urgent need to understand how fisheries affect these vulnerable marine ecosystems. At the same time, the impact of other fishing gear and small-scale fisheries remains sparsely known despite anecdotal evidence suggesting their impact may be significant. This study aims to provide baseline information on coral bycatch by bottom-set gillnets used by artisanal fisheries in Sagres (Algarve, southwestern Portugal), thereby contributing to understand the impact of the activity but also the diversity and abundance of corals in this region. Coral bycatch frequency and species composition were quantified over two fishing seasons (summer-autumn and spring) for 42 days. The relationship with fishing effort was characterized according to métiers (n = 6). The results showed that 85% of the gillnet deployments caught corals. The maximum number of coral specimens per net was observed in a deployment targeting Lophius budegassa (n = 144). In total, 4,326 coral fragments and colonies of 22 different species were captured (fishing depth range of 57–510 m, mean 139 ± 8 m). The most affected species were Eunicella verrucosa (32%), Paramuricea grayi (29%), Dendrophyllia cornigera (12%), and Dendrophyllia ramea (6%). The variables found to significantly influence the amount of corals caught were the target species, net length, depth, and mesh size. The 22 species of corals caught as bycatch belong to Orders Alcyonacea (80%), Scleractinia (18%), Zoantharia (1%), and Antipatharia (1%), corresponding to around 13% of the coral species known for the Portuguese mainland coast. These results show that the impact of artisanal fisheries on circalittoral coral gardens and CWC is potentially greater than previously appreciated, which underscores the need for new conservation measures and alternative fishing practices. Measures such as closure of fishing areas, frequent monitoring onboard of fishing vessels, or the development of encounter protocols in national waters are a good course of action. This study highlights the rich coral gardens of Sagres and how artisanal fisheries can pose significant threat to corals habitats in certain areas.

Mitigating Seafood Waste Through a Bycatch Donation Program

Watson JT, Stram DL, Harmon J. Mitigating Seafood Waste Through a Bycatch Donation Program. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.576431/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1481182_45_Marine_20201112_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Discarding of prohibited, under-sized, or non-target finfish is a major problem globally. Many such unwanted or banned catches do not survive long enough to be released alive, creating complex ecological and policy issues for the fishing industry. In U.S. Federal waters, regulation requires bycatch to be avoided as practicable and bycatch of some finfish species is designated as prohibited species catch (PSC). By regulation, PSC cannot be retained or sold and it must be returned to the sea (dead or alive). Some PSC species have strict limits to further incentivize their avoidance and limit bycatch mortality and these limits can lead to fishery closures. Despite extensive efforts to avoid bycatch in the U.S. and elsewhere, unwanted catches still occur, creating the potential for substantial food waste. We present one rarely discussed approach to maximize the value of dead, unwanted or prohibited finfish catches. The Prohibited Species Donation (PSD) program utilizes trawl fishery PSC that would otherwise be discarded by instead donating it to hunger relief organizations. This program simultaneously provides food and reduces waste while avoiding inadvertent incentives for catching prohibited species. For 26 years, the non-profit organization, SeaShare, has worked with the Alaska seafood industry to distribute 2,660 t (∼23.5 million servings) of prohibited species donations (salmon and halibut), high quality seafood that would have otherwise been discarded due to prohibition on retention. The PSD program provides an example that addresses food security and social value, an under-represented perspective in the global dialogue on unwanted catches.

Entanglement rates and haulout abundance trends of Steller (Eumetopias jubatus) and California (Zalophus californianus) sea lions on the north coast of Washington state

Allyn EMarina, Scordino JJoseph. Entanglement rates and haulout abundance trends of Steller (Eumetopias jubatus) and California (Zalophus californianus) sea lions on the north coast of Washington state Wells B. PLOS ONE [Internet]. 2020 ;15(8):e0237178. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237178
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Entanglements affect marine mammal species around the globe, and for some, those impacts are great enough to cause population declines. This study aimed to document rates and causes of entanglement and trends in local haulout abundance for Steller and California sea lions on the north coast of Washington from 2010–2018. We conducted small boat surveys to count sea lions and document entangled individuals. Rates of entanglement and entangling material occurrence were compared with records of stranded individuals on the Washington and Oregon coast and with packing bands recorded during beach debris surveys. The rate of entanglement for California sea lions was 2.13%, almost entirely composed of adult males, with a peak rate during June and July potentially due to some entangled individuals not migrating to their breeding grounds. For Steller sea lions, the rate of entanglement was 0.41%, composed of 77% adults (32.4% male, 63.3% female), 17.1% juveniles, 5.9% unknown age, and no pups. Steller sea lions exhibited a 7.9% ± 3.2 rate of increase in abundance at the study haulouts, which was similar to that seen in California sea lions (7.8% ± 4.2); both increases were greater than the population growth rates observed range-wide despite high rates of entanglement. Most entanglements for both species were classified as packing bands, followed by entanglement scars. Salmon flashers were also prevalent and only occurred from June–September during the local ocean salmon troll fishery. Packing band occurrence in beach debris surveys correlated with packing band entanglements observed on haulouts. However, no packing band entanglements were observed in the stranding record and the rate of stranded animals exhibiting evidence of entanglement was lower than expected, indicating that entanglement survival is higher than previously assumed. Future studies tracking individual entanglement outcomes are needed to develop effective, targeted management strategies.

Using GIS and stakeholder involvement to innovate marine mammal bycatch risk assessment in data-limited fisheries

Verutes GM, Johnson AF, Caillat M, Ponnampalam LS, Peter C, Vu L, Junchompoo C, Lewison RL, Hines EM. Using GIS and stakeholder involvement to innovate marine mammal bycatch risk assessment in data-limited fisheries Duplisea DE. PLOS ONE [Internet]. 2020 ;15(8):e0237835. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237835
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Fisheries bycatch has been identified as the greatest threat to marine mammals worldwide. Characterizing the impacts of bycatch on marine mammals is challenging because it is difficult to both observe and quantify, particularly in small-scale fisheries where data on fishing effort and marine mammal abundance and distribution are often limited. The lack of risk frameworks that can integrate and visualize existing data have hindered the ability to describe and quantify bycatch risk. Here, we describe the design of a new geographic information systems tool built specifically for the analysis of bycatch in small-scale fisheries, called Bycatch Risk Assessment (ByRA). Using marine mammals in Malaysia and Vietnam as a test case, we applied ByRA to assess the risks posed to Irrawaddy dolphins (Orcaella brevirostris) and dugongs (Dugong dugon) by five small-scale fishing gear types (hook and line, nets, longlines, pots and traps, and trawls). ByRA leverages existing data on animal distributions, fisheries effort, and estimates of interaction rates by combining expert knowledge and spatial analyses of existing data to visualize and characterize bycatch risk. By identifying areas of bycatch concern while accounting for uncertainty using graphics, maps and summary tables, we demonstrate the importance of integrating available geospatial data in an accessible format that taps into local knowledge and can be corroborated by and communicated to stakeholders of data-limited fisheries. Our methodological approach aims to meet a critical need of fisheries managers: to identify emergent interaction patterns between fishing gears and marine mammals and support the development of management actions that can lead to sustainable fisheries and mitigate bycatch risk for species of conservation concern.

Switching Gillnets to Longlines: An Alternative to Mitigate the Bycatch of Franciscana Dolphins (Pontoporia blainvillei) in Argentina

Berninsone LG, Bordino P, Gnecco M, Foutel M, Mackay AI, Werner TB. Switching Gillnets to Longlines: An Alternative to Mitigate the Bycatch of Franciscana Dolphins (Pontoporia blainvillei) in Argentina. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00699/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1418755_45_Marine_20200903_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The franciscana dolphin (Pontoporia blainvillei) is considered the most threatened cetacean in the South Western Atlantic due to bycatch in gillnet fisheries of Argentina, Uruguay, and Brazil. As gillnet fisheries operate in the same areas inhabited by dolphins, methods and strategies to reduce bycatch require particular attention. This study investigated the potential of switching gillnets to bottom longlines to reduce franciscana bycatch rates while maintaining economic returns in a small-scale artisanal fishery in Argentina. Trials were conducted in Bahía Samborombón and Cabo San Antonio between October 2004 and January 2007, in cooperation with artisanal fishermen who simultaneously fished using bottom longlines and gillnets. Target and non-target catch composition, fishing yield, catch size distribution and quality of catch, as well as bycatch of dolphins, sea turtles, and interaction with sea lions were compared between the two fishing methods to assess the profitability of switching fishing gears. Hauls of both gear types deployed simultaneously in the same locations showed similar fish catch composition and catch size with both gears but reduced catch of juvenile fishes in longlines. Bycatch of franciscana in bottom longlines was limited to only one dolphin in three consecutive years of trials, and no direct interaction between turtles and hooks were recorded. The economic analysis showed financially acceptable perspectives under a 5-year scenario. Reducing gillnet effort by switching to bottom longlines appears a practical approach to creating a sustainable fishery that could result in significant mitigation of current bycatch of franciscana dolphins in Argentina. However, implementation requires acceptance and compliance by the artisanal gillnet fishery.

Using GIS and stakeholder involvement to innovate marine mammal bycatch risk assessment in data-limited fisheries

Verutes GM, Johnson AF, Caillat M, Ponnampalam LS, Peter C, Vu L, Junchompoo C, Lewison RL, Hines EM. Using GIS and stakeholder involvement to innovate marine mammal bycatch risk assessment in data-limited fisheries. PLOS ONE [Internet]. 2020 ;15(8):e0237835. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237835
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Fisheries bycatch has been identified as the greatest threat to marine mammals worldwide. Characterizing the impacts of bycatch on marine mammals is challenging because it is difficult to both observe and quantify, particularly in small-scale fisheries where data on fishing effort and marine mammal abundance and distribution are often limited. The lack of risk frameworks that can integrate and visualize existing data have hindered the ability to describe and quantify bycatch risk. Here, we describe the design of a new geographic information systems tool built specifically for the analysis of bycatch in small-scale fisheries, called Bycatch Risk Assessment (ByRA). Using marine mammals in Malaysia and Vietnam as a test case, we applied ByRA to assess the risks posed to Irrawaddy dolphins (Orcaella brevirostris) and dugongs (Dugong dugon) by five small-scale fishing gear types (hook and line, nets, longlines, pots and traps, and trawls). ByRA leverages existing data on animal distributions, fisheries effort, and estimates of interaction rates by combining expert knowledge and spatial analyses of existing data to visualize and characterize bycatch risk. By identifying areas of bycatch concern while accounting for uncertainty using graphics, maps and summary tables, we demonstrate the importance of integrating available geospatial data in an accessible format that taps into local knowledge and can be corroborated by and communicated to stakeholders of data-limited fisheries. Our methodological approach aims to meet a critical need of fisheries managers: to identify emergent interaction patterns between fishing gears and marine mammals and support the development of management actions that can lead to sustainable fisheries and mitigate bycatch risk for species of conservation concern.

Guidelines for the Safe and Humane Handling and Release of Bycaught Small Cetaceans from Fishing Gear

Hamer DJ, Minton G. Guidelines for the Safe and Humane Handling and Release of Bycaught Small Cetaceans from Fishing Gear. Bonn, Germany: UNEP/CMS & WWF; 2020 p. 50. Available from: https://www.cms.int/en/publication/guidelines-safe-and-humane-handling-and-release-bycaught-small-cetaceans-fishing-gear
Freely available?: 
Yes
Summary available?: 
No
Type: Report

These guidelines, in their full text format, are intended to provide fisheries managers at any level, as well as those who work with fisheries to improve their sustainability, with bestpractice methodology on the safe and humane handling and release of small cetaceans accidentally bycaught in fishing gear. They are intended to enable managers and ‘trainers’, as well as anyone involved with fisheries policy or management to understand the rationale and need for ‘best practice’, as well as the science that supports the recommended practices.

The illustrations provided with these guidelines, as well as the bullet-pointed handling notes, can be used to develop 2-page laminated fisher-friendly ‘Flips’ (ready reckoners) that contain clear, concise, bullet-pointed instructions pertinent to each specific fishery.

Mitigation of Elasmobranch Bycatch in Trawlers: A Case Study in Indian Fisheries

Gupta T, Booth H, Arlidge W, Rao C, Manoharakrishnan M, Namboothri N, Shanker K, Milner-Gulland EJ. Mitigation of Elasmobranch Bycatch in Trawlers: A Case Study in Indian Fisheries. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00571/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1391749_45_Marine_20200730_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Bycatch poses a significant threat to marine megafauna, such as elasmobranchs. India has one of the highest elasmobranch landings globally, through both targeted catch and bycatch. As elasmobranchs contribute to food and livelihood security, there is a need for holistic approaches to bycatch mitigation. We adopt an interdisciplinary approach to critically assess a range of hypothetical measures for reducing elasmobranch capture in a trawler fishery on India’s west coast, using a risk-based mitigation hierarchy framework. Data were collected through landing surveys, interviews and a literature review, to assess the following potential management options for their technical effectiveness and socio-economic feasibility: (1) spatio-temporal closures; (2) net restrictions; (3) bycatch reduction devices (BRDs); and (4) live onboard release. Our study provides the first evidence-based and nuanced understanding of elasmobranch bycatch management for this fishery, and suggestions for future conservation and research efforts. Onboard release may be viable for species like guitarfish, with moderate chances of survival, and was the favored option among interview respondents due to minimal impact on earnings. While closures, net restrictions and BRDs may reduce elasmobranch capture, implementation will be challenging under present circumstances due to the potentially high impact on fisher income. Interventions for live release can therefore be used as a step toward ameliorating bycatch, while initiating longer-term engagement with the fishing community. Participatory monitoring can help address critical knowledge gaps in elasmobranch ecology. Spatio-temporal closures and gear restriction measures may then be developed through a bottom-up approach in the long term. Overall, the framework facilitated a holistic assessment of bycatch management to guide decision-making. Scaling-up and integrating such case studies across different species, fisheries and sites would support the formulation of a meaningful management plan for elasmobranch fisheries in India.

Toward elimination of unwanted catches using a 100 mm T90 extension and codend in demersal mixed fisheries

Robert M, Morandeau F, Scavinner M, Fiche M, Larnaud P. Toward elimination of unwanted catches using a 100 mm T90 extension and codend in demersal mixed fisheries Patterson HM. PLOS ONE [Internet]. 2020 ;15(7):e0235368. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0235368
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Most European fishing fleets will need to drastically reduce their unwanted catches to comply with new rules of the common fisheries policy. A more practical way to avoid increasing on-board sorting time and issues linked to storage capacity is to prevent unwanted catches in the first place. We assessed the selectivity properties of an experimental fishing gear that combined a 100 mm T90 cylinder with 130 meshes in the extension and a 100 mm T90 codend of 33 meshes (experimental gear) compared to a 100 mm diamond mesh extension and codend (control gear) during commercial trips using twin trawls. Analysis of the relative size composition of catches indicated a significantly higher escapement of small fish of several target species (e.g. Lepidorhombus whiffiagonisMelanogrammus aeglefinusRaja spp, and Lophius spp) and non-target species (e.g. Capros aper and Gurnards spp) from the T90 experimental trawl compared to the control trawl (n = 49 hauls), resulting in a significant reduction of unwanted catches of Gadidae, Triglidae, and Caproidae. In contrast, non-negligible commercial losses of small grade target gadoid species were observed. Mixed general linear models showed that the proportion of ray, haddock and anglerfish retained per length class decreased with increased tow duration. The T90 experimental gear will perform at a commercial level when targeting monkfish, megrim, rays and large haddock, however fishers are not likely to use this gear when targeting smaller-bodied species such as cephalopods, small haddock, whiting (Merlangius merlangus) and hake (Merluccius merluccius), because the gear is likely to allow large numbers to escape. Selectivity studies often focus on a short list of target species; however, catches of non-target species under quota can be problematic for some fisheries. For example, under the implementation of the Landing Obligation catches of boarfish could choke the French whitefish demersal fisheries in the Celtic sea, as France has no national quota for that species. The device tested constitutes an efficient solution to mitigate catches for such non-target schooling fish.

Assessing the Effects of Banana Pingers as a Bycatch Mitigation Device for Harbour Porpoises (Phocoena phocoena)

Omeyer LCM, Doherty PD, Dolman S, Enever R, Reese A, Tregenza N, Williams R, Godley BJ. Assessing the Effects of Banana Pingers as a Bycatch Mitigation Device for Harbour Porpoises (Phocoena phocoena). Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00285/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1334659_45_Marine_20200521_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Bycatch is a significant cause of population declines of marine megafauna globally. While numerous bycatch mitigation strategies exist, acoustic alarms, or pingers, are the most widely adopted strategy for small cetaceans. Although pingers have been shown to be an effective measure for numerous species, there are some concerns about their long-term use. Bycatch is recognized as a persistent problem in waters around Cornwall, United Kingdom, where several cetacean species are resident, with harbour porpoises (Phocoena phocoena) being the most-commonly sighted. In this study, we assessed the effects of a Banana Pinger (Fishtek Marine Limited) on harbour porpoises in Cornwall between August 2012 and March 2013. Two passive acoustic loggers (C-PODs; Chelonia Limited) were deployed 100 m apart to record cetacean activity during cycles of active and inactive pinger periods. Harbour porpoises were 37% less likely to be detected at the C-POD near the pinger when the pinger was active, while they were only 9% less likely to be detected 100 m further away. The effect of the pinger was constant over the study period at both C-PODs despite the temporal variation in harbour porpoise detections. In addition, we found no evidence of reduced pinger effect with changing environmental conditions. Furthermore, harbour porpoise detections at the C-POD near the pinger did not depend on the time elapsed since the pinger turned off, with harbour porpoises returning to the ensonified area with no delay. Together these results suggest that (1) harbour porpoises did not habituate to the pinger over an 8-month period, (2) the pinger effect is very localized, and (3) pinger use did not lead to harbour porpoise displacement over the study period, suggesting an absence of long-term behavioral effects. We suggest that the deployment of pingers on fishing nets would likely reduce net-porpoise interactions, thereby mitigating bycatch of harbour porpoises and potentially other cetacean species. As the small-scale fishery dominates in United Kingdom waters, there is an acute need for cost-effective mitigation strategies with concurrent monitoring to be implemented rapidly in order to address the problem of harbour porpoise, and more generally, cetacean bycatch.

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