Small cetacean captures and CPUE estimates in artisanal fisheries operating from a port in northern Peru, 2005-2007. Scientific Committee document SC/60/SM19, International Whaling Commission, June 2008, Santiago, Chile

This work provides the first direct, at-sea monitoring of small cetacean interactions with Peruvian artisanal drift gillnet and longline vessels. A total of 253 small cetaceans were observed captured during 66 fishing trips (480 sets) monitored from March 2005-July 2007 in the port of Salaverry, northern Peru. Interactions consisted of 231 animals caught in gillnets, 1 in a longline and 21 direct takes by harpooning for use as bait. The most commonly captured species were long-beaked common dolphins Delphinus capensis, dusky dolphins Lagenorhynchus obscurus, common bottlenose dolphins Tursiops truncates (offshore stock) and Burmeister’s porpoises Phocoena spinipinnis. Overall bycatch CPUE (catch per unit effort) was estimated to be 0.677 animals/set and 0.007 animals/set for gillnet and longline vessels, respectively. Based upon total fishing effort for the port, we estimated the average of small cetacean bycatch at 2,623 animals/year (CI 2,061-3,185) for 2002-2007. This work indicates that, in at least one Peruvian port, bycatch and harpooning of small cetaceans persist at high levels and on a regular basis, particularly in driftnet vessels. The formerly unknown practice of at-sea discarding of carcasses stands in sharp contrast with current, high small cetacean discard rates (49%) found in this study. That, combined with high prices/lack of availability of traditional bait fish suggest that small cetacean bycatch and harpooning could now potentially be reduced through the implementation of bycatch mitigation measures and greater accessibility to preferred bait

Reflection tomography of time-lapse GPR data for studying dynamic unsaturated flow phenomena

Ground-penetrating radar (GPR) reflection tomography algorithms allow non-invasive monitoring of water content changes resulting from flow in the vadose zone. The approach requires multi-offset GPR data that are traditionally slow to collect. We automate GPR data collection to reduce the survey time significantly, thereby making this approach to hydrologic monitoring feasible. The method was evaluated using numerical simulations and laboratory experiments that suggest reflection tomography can provide water content estimates to within 5 % vol vol−1–10 % vol vol−1 for the synthetic studies, whereas the empirical estimates were typically within 5 %–15 % of measurements from in situ probes. Both studies show larger observed errors in water content near the periphery of the wetting front, beyond which additional reflectors were not present to provide data coverage. Overall, coupling automated GPR data collection with reflection tomography provides a new method for informing models of subsurface hydrologic processes and a new method for determining transient 2-D soil moisture distributions

Distribution and habitat use of a cryptic small cetacean, the Burmeister's porpoise, monitored from a small-scale fishery platform

This is the final version. Available from Frontiers Media via the DOI in this record. There is widespread evidence that small-scale fisheries (SSF) bycatch threatens many populations of small cetaceans, yet conservation efforts are often limited by a lack of basic knowledge regarding their abundance, distribution, and habitat use. Here, we used passive acoustic monitoring from an SSF platform-of-opportunity to better characterize the distribution and habitat use of small cetaceans in northern Peru, focussing on the little-known Burmeister's porpoise Phocoena spinipinnis. From 2009 to 2012, acoustic click detectors (C-PODs) were attached to fishing nets for the duration of 116 fishing sets (30 fishing trips). Dolphins (unspecified delphinids) and porpoises were recorded around 71 and 22% of fishing sets, respectively. The probability of occurrence and buzzing behavior (a proxy for foraging), and time spent, were linked to both static and dynamic environmental variables to examine the drivers of habitat use. Dolphin activity was spread evenly throughout the fishing area and was not linked to any habitat variables. In contrast, porpoises were detected in neritic waters, and habitat models performed well, identifying preferences for shallow (< 200 m depth) and cooler (17-18°C) waters, close (< 50 km) to shore. The high bycatch rate of small cetaceans in Peruvian SSF gave us the unique opportunity to investigate the link between bycatch and cetacean activity around vessels. We found a positive relationship between the likelihood of a bycatch event and acoustic presence for both dolphins and porpoises, however as we did not know the timing of entanglement, we could not link vocalization rates to mortality events. Nonetheless, as small cetaceans (particularly dolphins) frequently encounter fishing boats, the likelihood of entanglements may be reduced through effective efforts to alert animals to the presence of the net, either acoustically (using acoustic alarms) or visually. This study demonstrates that passive acoustic monitoring from a fisheries platform can provide insights into the distribution and habitat use of small cetaceans at relatively low cost, and is likely to be suitable in regions with low monitoring effort and high fishing pressure.Natural Environment Research CouncilEuropean UnionDarwin Initiativ

Remote electronic monitoring as a potential alternative to on-board observers in small-scale fisheries

This is the final version of the article. Available from Elsevier via the DOI in this record.Small-scale fisheries can greatly impact threatened marine fauna. Peru's small-scale elasmobranch gillnet fishery captures thousands of sharks and rays each year, and incidentally captures sea turtles, marine mammals and seabirds. We assessed the ability of a dedicated fisheries remote electronic monitoring (REM) camera to identify and quantify captures in this fishery by comparing its performance to on-board observer reports. Cameras were installed across five boats with a total of 228 fishing sets monitored. Of these, 169 sets also had on-board fisheries observers present. The cameras were shown to be an effective tool for identifying catch, with > 90% detection rates for 9 of 12 species of elasmobranchs caught. Detection rates of incidental catch were more variable (sea turtle = 50%; cetacean = 80%; pinniped = 100%). The ability to quantify target catch from camera imagery degraded for fish quantities exceeding 15 individuals. Cameras were more effective at quantifying rays than sharks for small catch quantities (x ≤ 15 fish), whereas size affected camera performance for large catches (x > 15 fish). Our study showed REM to be effective in detecting and quantifying elasmobranch target catch and pinniped bycatch in Peru's small-scale fishery, but not, without modification, in detecting and quantifying sea turtle and cetacean bycatch. We showed REM can provide a time- and cost-effective method to monitor target catch in small-scale fisheries and can be used to overcome some deficiencies in observer reports. With modifications to the camera specifications, we expect performance to improve for all target catch and bycatch species.This work was supported by the Darwin Initiative Project EIDP0046 and the Whitley Fund for Nature Grant 150626 CF15. David C. Bartholomew is supported by a NERC studentship NE/L002434/1

Big catch, little sharks: Insight into Peruvian small-scale longline fisheries.

PublishedJournal ArticleThis is the final version of the article. Available from Wiley Open Access via the DOI in this record.Shark take, driven by vast demand for meat and fins, is increasing. We set out to gain insights into the impact of small-scale longline fisheries in Peru. Onboard observers were used to document catch from 145 longline fishing trips (1668 fishing days) originating from Ilo, southern Peru. Fishing effort is divided into two seasons: targeting dolphinfish (Coryphaena hippurus; December to February) and sharks (March to November). A total of 16,610 sharks were observed caught, with 11,166 identified to species level. Of these, 70.6% were blue sharks (Prionace glauca), 28.4% short-fin mako sharks (Isurus oxyrinchus), and 1% were other species (including thresher (Alopias vulpinus), hammerhead (Sphyrna zygaena), porbeagle (Lamnus nasus), and other Carcharhinidae species (Carcharhinus brachyurus, Carcharhinus falciformis, Galeorhinus galeus). Mean ± SD catch per unit effort of 33.6 ± 10.9 sharks per 1000 hooks was calculated for the shark season and 1.9 ± 3.1 sharks per 1000 hooks were caught in the dolphinfish season. An average of 83.7% of sharks caught (74.7% blue sharks; 93.3% mako sharks) were deemed sexually immature and under the legal minimum landing size, which for species exhibiting k-selected life history traits can result in susceptibility to over exploitation. As these growing fisheries operate along the entire Peruvian coast and may catch millions of sharks per annum, we conclude that their continued expansion, along with ineffective legislative approaches resulting in removal of immature individuals, has the potential to threaten the sustainability of the fishery, its target species, and ecosystem. There is a need for additional monitoring and research to inform novel management strategies for sharks while maintaining fisher livelihoods.We would like to thank the members of the fishing communities who participated in this study, in particular the fishers who were willing to have an observer onboard. We acknowledge Pro Delphinus staff: Bernedo, Cuentas, Lopez, and Mamani, for their help in data collection. We are thankful also to Pro Delphinus staff Natalia Ortiz and Nadia Balducci for support in data entry. This study was conducted in conjunction with and funded by the Darwin Initiative Sustainable Artisanal Fisheries Initiative in Peru and an initial grant from the Oak Foundation through Duke University. MJW was funded by PRIMaRE. JAS and JCM received support from ORSAS and University of Exeter, respectively

Illuminating gillnets to save seabirds and the potential for multi-taxa bycatch mitigation

This is the final version. Available from Royal Society via the DOI in this record. Bycatch in net fisheries is recognized as a major source of mortality for many marine species, including seabirds. Few mitigation solutions, however, have been identified. We assessed the effectiveness of illuminating fishing nets with green light emitting diodes (LEDs) to reduce the incidental capture of seabirds. Experiments were conducted in the demersal, set gillnet fishery of Constante, Peru and compared 114 pairs of control and illuminated nets. We observed captures of a total of 45 guanay cormorants (Phalacrocorax bougainvillii), with 39 caught in control nets and six caught in illuminated nets. Seabird bycatch in terms of catch-per-unit-effort was significantly (p < 0.05) higher in control nets than in illuminated nets, representing an 85.1% decline in the cormorant bycatch rate. This study, showing that net illumination reduces seabird bycatch and previous studies showing reductions in sea turtle bycatch without reducing target catch, indicates that net illumination can be an effective multi-taxa bycatch mitigation technique. This finding has broad implications for bycatch mitigation in net fisheries given LED technology's relatively low cost, the global ubiquity of net fisheries and the current paucity of bycatch mitigation solutions.Department for Environment, Food and Rural Affairs (DEFRA)NOAA Fisheries ServiceNational Fish and Wildlife Foundatio

Small-scale fisheries of Peru: a major sink for marine turtles in the Pacific

1. Over the last few decades, evidence of marine vertebrate bycatch has been collected for a range of industrial fisheries. It has recently been acknowledged that large impacts may also result from similar interactions with small-scale fisheries (SSF) due largely to their diffuse effort and large number of vessels in operation. Marine mammals, seabirds, turtles as well as some shark species have been reported as being impacted by SSF worldwide. 2. From 2000 to 2007, we used both shore-based and onboard observer programmes from three SSF ports in Peru to assess the impact on marine turtles of small-scale longline, bottom set nets and driftnet fisheries. 3. We reported a total of 807 sea turtles captured, 91Æ8% of which were released alive. For these three sites alone, we estimated c. 5900 turtles captured annually (3200 loggerhead turtles Caretta caretta, 2400 green turtles Chelonia mydas, 240 olive ridleys Lepidochelys olivacea and 70 leatherback turtles Dermochelys coriacea). 4. SSF in Peru are widespread and numerous (\u3e100 ports, \u3e9500 vessels, \u3e37 000 fishers), and our observed effort constituted c. 1% of longline and net deployments. We suggest that the number of turtles captured per year is likely to be in the tens of thousands. Thus, the impacts of Peruvian SSF have the potential to severely impact sea turtles in the Pacific especially green, loggerhead and leatherback turtles. 5. Implications of the human use of turtle products as ‘marine bushmeat’ are also raised as an important issue. Although such utilization is illegal, it is difficult to foresee how it can be managed without addressing the constraints to the livelihoods of those depending almost entirely on coastal resources. 6. Syntheses and applications. Our analysis demonstrates that, despite logistical challenges, it is feasible to estimate the bycatch per unit of effort in SSF by combining methods that account for fishing effort and bycatch, such as using onboard and shore-based observers. We highlight sea turtle bycatch in SSF in the southeast Pacific as a major conservation concern but also suggest possible paths for mitigation

Reducing green turtle bycatch in small-scale fisheries using illuminated gillnets: The Cost of Saving a Sea Turtle

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Gillnet fisheries exist throughout the oceans and have been implicated in high bycatch rates of sea turtles. In this study, we examined the effectiveness of illuminating nets with light-emitting diodes (LEDs), placed on floatlines in order to reduce sea turtle bycatch in a small-scale bottom-set gillnet fishery. In Sechura Bay, Northern Peru, 114 pairs of control and illuminated nets were deployed. The predicted mean Catch Per Unit of Effort (CPUE) of target species, standardized for environmental variables using generalized additive model analysis, was similar for both control and illuminated nets. In contrast, the predicted mean CPUE of green turtles (Chelonia mydas) was reduced by 63.9% in illuminated nets. One hundred twenty-five green turtles were caught in control nets while 62 were caught in illuminated nets. This statistically significant reduction (GAM analysis, p<0.05) in sea turtle bycatch suggests that net illumination could be an effective conservation tool. Challenges to implementing the use of LEDs include equipment costs, increased net handling times, and limited awareness among fishermen regarding the effectiveness of this technology. Cost estimates for preventing a single sea turtle catch are as low as $34 USD, while the costs to outfit the entire gillnet fishery in Sechura Bay can be as low as$9200 USD. Understanding these cost challenges emphasizes the need for institutional support from national ministries, international non-governmental organizations and the broader fisheries industry to make possible widespread implementation of net illumination as a sea turtle bycatch reduction strategy.ProDelphinusDarwin InitiativeNational Marine Fisheries Service of the National Oceanic and Atmospheric AdministrationUniversity of Hawaii Joint Institute for Marine and Atmospheric Researc