The analysis of cetacean strandings can provide fundamental information about species diversity and composition in a particular region. The present study collected and analyzed cetacean strandings, bycatches and rescu...The analysis of cetacean strandings can provide fundamental information about species diversity and composition in a particular region. The present study collected and analyzed cetacean strandings, bycatches and rescues along the western coast of the Taiwan Strait, China, from 2010 to 2015. In total, 48 records, including 37 strandings, 8 bycatches and 3 rescues, involving 13 known species were collected. Among them, Indo-Pacific humpback dolphins（Sousa chinensis） and finless porpoises（Neophocaena phocaenoides） were the most common species, consisting of 31.3% and 25%, respectively. Notably, 10 out of the 48（20.8%） records were collected from the Pingtan Island and included 3 species of Mysticeti and 4 species of Odontoceti. Finally, we compared the cetacean species composition between the western and eastern coasts of the Taiwan Strait; 31 cetacean species occurred in the Taiwan Strait, indicating a relatively high cetacean diversity in this region. Systematic field surveys are urgently needed to explore the cetacean species composition, population stock and the related habitat status in the Taiwan Strait, which may improve conservation management in the future.展开更多
The issue of bycatch in the fisheries sector has been a major concern for the marine biologists over few decades in terms of conservation of marine eco-system and sustainability of the fisheries sector and marine biod...The issue of bycatch in the fisheries sector has been a major concern for the marine biologists over few decades in terms of conservation of marine eco-system and sustainability of the fisheries sector and marine biodiversity.As far as the concept of Bycatch is concerned,these are the unwanted species having less commercial importance,which in most of the cases disposed into the seas onboard or are caught during fishing.The article discusses the social,economic,cultural,and environmental impacts in addressing the issue of bycatch.The concern regarding bycatch is relatively new in the horizon in Indian perspective though it is often considered a major issue faced by developed nations since long.The problem of bycatch poses a serious threat to livelihoods and food security as it acts as a precursor to depletion of the food sources for local consumption with adverse social,economic,cultural,and environmental impacts.The adverse effects of by-catch can be mitigated through commercialisation of bycatch and making profits from the sale of bycatch,opening up of new markets for bycatch species or products,uses of bycatch as fishmeal and application of bycatch reduction devices(BRDs).Reorientation of the present monitoring system to collect fisheries data,strengthening technical know-how,bringing effective policy intervention,efficient co-management,and sincere and honest efforts in reducing bycatch and discards may provide a considerable impact towards sustainability of marine eco-system.展开更多
The offshore Northern shrimp(Pandalus borealis)bottom trawl fishery in eastern Canada currently uses 22 and 28 mm bar spacing Nordmøre grids to limit bycatch from using small mesh codends.However,a recent rebound...The offshore Northern shrimp(Pandalus borealis)bottom trawl fishery in eastern Canada currently uses 22 and 28 mm bar spacing Nordmøre grids to limit bycatch from using small mesh codends.However,a recent rebound of juvenile redfish(Sebastes spp.),that can pass through the grids,has greatly increased bycatch.To address this concern,this study investigated the effectiveness of 17 and 15 mm bar spacing Nordmøre grids in a twin-trawl(paired)configuration against the traditional 22 mm bar spacing grid.Size selectivity analyses showed that the 17 and 15 mm grids resulted in no significant reduction in shrimp catch across all length classes.The 17 mm grid significantly reduced redfish bycatch for all length classes and the 15 mm grid significantly reduced redfish bycatch for individuals larger than 95 mm total length.Less redfish entered the codend with the experimental grids,however,the overlap in width between redfish and Northern shrimp limits the overall sorting efficiency of the grids,leaving some redfish still vulnerable to capture.展开更多
Longline fisheries for tunas and tuna-like species present an existential threat to many populations of albatrosses and petrels worldwide. To prevent this form of mortality we developed a new technology designed to de...Longline fisheries for tunas and tuna-like species present an existential threat to many populations of albatrosses and petrels worldwide. To prevent this form of mortality we developed a new technology designed to deploy baited hooks underwater beyond the dive depths of?seabirds (6 - 10 m for the species most commonly caught). The underwater bait setter is a stern-mounted, hydraulically-operated and computer-controlled?device that catapults?baited hooks underwater in a steel capsule?connected to hydraulic winches by Spectra®rope. Baits are flushed from the capsule by water pressure through a spring-loaded bait release door. The chief engineering challenges in the developmental stageswere ensuring:?1) bait delivery?to target depths with cycle times (time from release to recovery) that were practical for fishing operations;?2) bait retention in the capsule (no drop-outs) on the descent phase of the cycle;?3) baits, upon?release at target depth, were not drawn up the water column on the capsule recovery phase (from possible hook-ups and/or suction);and?4) the retention of baits?on?hooks post-release from the capsule was not affected by the mechanical release underwater. Operational trials with the final version of the capsule yielded?satisfactory cycle times to depths of 6 - 10 m. All baits were retained?in the capsule on the descent and?released as required?at target depths (n = 606 deployments). Bait retention on hooks post release from the capsule and retention on hooks hand-set at the surface (the conventional method) were statistically indistinguishable.?The underwater bait setter is modular in construction and can be fitted to all types of vessel sterns.展开更多
<span style="font-family:Verdana;">Chimaeras</span><span style="font-family:;" "=""><span style="font-family:Verdana;">, fish in the order Chimaerif...<span style="font-family:Verdana;">Chimaeras</span><span style="font-family:;" "=""><span style="font-family:Verdana;">, fish in the order Chimaeriformes, are among the rarest and least studied fish in the class Chondrichthyes (cartilaginous fish). Previous records have indicated that a species of chimaera known as the elephantfish, or cockfish, </span><i><span style="font-family:Verdana;">Callorhinchus callorynchus</span></i><span style="font-family:Verdana;">, may be found in marine waters off southeastern Brazil, as far north as the state of S<span style="font-size:10.0pt;font-family:"">ã</span>o Paulo. Here we report that </span><i><span style="font-family:Verdana;">C. callorynchus</span></i><span style="font-family:Verdana;">, caught with bottom gillnet, was found in an urban fish market in the city of Rio de Janeiro (~23<span style="white-space:nowrap;">˚</span>S). This and other records from a variety of places call into question the distribution limits of the American elephantfish in the southwestern Atlantic Ocean and whether, at least seasonally, this species may often be found as far north as the state of Rio de Janeiro. Because of scientific and conservation interests in the poorly known Chimaeriformes, we recommend long-term monitoring of the fish catch in ports along the southern Brazilian coast, to better understand the natural history of the intriguing chimeras.</span></span>展开更多
基金The National Natural Science Foundation for Young Scholars of China under contract No.41506164the foundation of the State Oceanic Administration of China under contract No.201105011+3 种基金the Natural Science Foundation for Young Scholars of Fujian Province under contract No.2017J05062China-ASEAN maritime cooperation fund under contract No.HX150702the foundation of the Ministry of Agriculture of the People’s Republic of China under contract No.1070413701307the Ocean Park Conservation Foundation,Hong Kong(OPCFHK)under contract No.MM03_1617
文摘The analysis of cetacean strandings can provide fundamental information about species diversity and composition in a particular region. The present study collected and analyzed cetacean strandings, bycatches and rescues along the western coast of the Taiwan Strait, China, from 2010 to 2015. In total, 48 records, including 37 strandings, 8 bycatches and 3 rescues, involving 13 known species were collected. Among them, Indo-Pacific humpback dolphins（Sousa chinensis） and finless porpoises（Neophocaena phocaenoides） were the most common species, consisting of 31.3% and 25%, respectively. Notably, 10 out of the 48（20.8%） records were collected from the Pingtan Island and included 3 species of Mysticeti and 4 species of Odontoceti. Finally, we compared the cetacean species composition between the western and eastern coasts of the Taiwan Strait; 31 cetacean species occurred in the Taiwan Strait, indicating a relatively high cetacean diversity in this region. Systematic field surveys are urgently needed to explore the cetacean species composition, population stock and the related habitat status in the Taiwan Strait, which may improve conservation management in the future.
文摘The issue of bycatch in the fisheries sector has been a major concern for the marine biologists over few decades in terms of conservation of marine eco-system and sustainability of the fisheries sector and marine biodiversity.As far as the concept of Bycatch is concerned,these are the unwanted species having less commercial importance,which in most of the cases disposed into the seas onboard or are caught during fishing.The article discusses the social,economic,cultural,and environmental impacts in addressing the issue of bycatch.The concern regarding bycatch is relatively new in the horizon in Indian perspective though it is often considered a major issue faced by developed nations since long.The problem of bycatch poses a serious threat to livelihoods and food security as it acts as a precursor to depletion of the food sources for local consumption with adverse social,economic,cultural,and environmental impacts.The adverse effects of by-catch can be mitigated through commercialisation of bycatch and making profits from the sale of bycatch,opening up of new markets for bycatch species or products,uses of bycatch as fishmeal and application of bycatch reduction devices(BRDs).Reorientation of the present monitoring system to collect fisheries data,strengthening technical know-how,bringing effective policy intervention,efficient co-management,and sincere and honest efforts in reducing bycatch and discards may provide a considerable impact towards sustainability of marine eco-system.
文摘The offshore Northern shrimp(Pandalus borealis)bottom trawl fishery in eastern Canada currently uses 22 and 28 mm bar spacing Nordmøre grids to limit bycatch from using small mesh codends.However,a recent rebound of juvenile redfish(Sebastes spp.),that can pass through the grids,has greatly increased bycatch.To address this concern,this study investigated the effectiveness of 17 and 15 mm bar spacing Nordmøre grids in a twin-trawl(paired)configuration against the traditional 22 mm bar spacing grid.Size selectivity analyses showed that the 17 and 15 mm grids resulted in no significant reduction in shrimp catch across all length classes.The 17 mm grid significantly reduced redfish bycatch for all length classes and the 15 mm grid significantly reduced redfish bycatch for individuals larger than 95 mm total length.Less redfish entered the codend with the experimental grids,however,the overlap in width between redfish and Northern shrimp limits the overall sorting efficiency of the grids,leaving some redfish still vulnerable to capture.
文摘Longline fisheries for tunas and tuna-like species present an existential threat to many populations of albatrosses and petrels worldwide. To prevent this form of mortality we developed a new technology designed to deploy baited hooks underwater beyond the dive depths of?seabirds (6 - 10 m for the species most commonly caught). The underwater bait setter is a stern-mounted, hydraulically-operated and computer-controlled?device that catapults?baited hooks underwater in a steel capsule?connected to hydraulic winches by Spectra®rope. Baits are flushed from the capsule by water pressure through a spring-loaded bait release door. The chief engineering challenges in the developmental stageswere ensuring:?1) bait delivery?to target depths with cycle times (time from release to recovery) that were practical for fishing operations;?2) bait retention in the capsule (no drop-outs) on the descent phase of the cycle;?3) baits, upon?release at target depth, were not drawn up the water column on the capsule recovery phase (from possible hook-ups and/or suction);and?4) the retention of baits?on?hooks post-release from the capsule was not affected by the mechanical release underwater. Operational trials with the final version of the capsule yielded?satisfactory cycle times to depths of 6 - 10 m. All baits were retained?in the capsule on the descent and?released as required?at target depths (n = 606 deployments). Bait retention on hooks post release from the capsule and retention on hooks hand-set at the surface (the conventional method) were statistically indistinguishable.?The underwater bait setter is modular in construction and can be fitted to all types of vessel sterns.
文摘<span style="font-family:Verdana;">Chimaeras</span><span style="font-family:;" "=""><span style="font-family:Verdana;">, fish in the order Chimaeriformes, are among the rarest and least studied fish in the class Chondrichthyes (cartilaginous fish). Previous records have indicated that a species of chimaera known as the elephantfish, or cockfish, </span><i><span style="font-family:Verdana;">Callorhinchus callorynchus</span></i><span style="font-family:Verdana;">, may be found in marine waters off southeastern Brazil, as far north as the state of S<span style="font-size:10.0pt;font-family:"">ã</span>o Paulo. Here we report that </span><i><span style="font-family:Verdana;">C. callorynchus</span></i><span style="font-family:Verdana;">, caught with bottom gillnet, was found in an urban fish market in the city of Rio de Janeiro (~23<span style="white-space:nowrap;">˚</span>S). This and other records from a variety of places call into question the distribution limits of the American elephantfish in the southwestern Atlantic Ocean and whether, at least seasonally, this species may often be found as far north as the state of Rio de Janeiro. Because of scientific and conservation interests in the poorly known Chimaeriformes, we recommend long-term monitoring of the fish catch in ports along the southern Brazilian coast, to better understand the natural history of the intriguing chimeras.</span></span>
