Catch and trade bans for seahorses can be negated by non-selective fisheries

1. All seahorse species (genus Hippocampus) are listed under Schedule I of India's Wild Life Protection Act, making all capture and trade of seahorses illegal. In the more than 15 years since the ban, little work has been done to assess its effects on seahorse conservation.
2. Between 2015 and 2017, fisheries and trade surveys were conducted along the south-east coast of India, in the state of Tamil Nadu, historically known to be a hub for seahorse catches and trade.
3. Seahorses were primarily landed as bycatch, although in greater quantities by traditional drag nets than as trawl bycatch. Total annual catches were estimated between 4.98 million and 13.64 million seahorses, 87% of which were caught by active non-selective gear.
4. Generalized additive models revealed that seahorse catch per unit effort had non-linear relations with depth and latitude, and were higher in biogenic habitats, with active, bottom-used, and non-selective gears (e.g. trawls).
5. The illegal nature of the trade in seahorses hampered an understanding of trade routes and trade volumes. Catch estimates indicated that 11.21–30.31 tonnes of seahorses probably entered trade, yet interviews with traders only documented trade of about 1.6 tonnes.
6. Fishers reported a decreasing availability of seahorses. Since most seahorses come from bycatch in persistent fisheries that are not directly affected by the ban on seahorse capture, this decline is likely to represent a population decline.
7. A fishery and trade ban for incidentally caught species, particularly in a poorly regulated fishery, appears to add little conservation value. There needs to be a shift in the management approach, moving from a ban towards spatial and temporal restrictions, and toward enforcing existing fishery regulations.

     

Assessing East African trade in seahorse species as a basis for conservation under international controls

• 1. Seahorses (Hippocampus spp.), many of which are listed as Vulnerable or Endangered on the IUCN Red List, are traded worldwide as souvenirs, aquarium fish and, primarily, for use in traditional medicines. Given concern over the sustainability of this trade, the genus was added to Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in May 2004.
• 2. This paper reports findings of the first ever survey of seahorse trade in Africa, conducted in Kenya and Tanzania in May and June 2000.
• 3. Seahorse trade in Kenya was found to be negligible, with approximately 10 live seahorses exported as aquarium fish annually. Until 1998, however, Kenya may have imported somewhere from 1 to 2.3 t of dried seahorses annually from Tanzania for re‐export to Asian medicine markets. Seahorse trade in Tanzania remained substantial, with at least 630–930 kg of dried seahorse exported directly to Asia each year.
• 4. Accounts of declines in seahorse availability and seahorse size, although few in number, could be early warning signs that wild populations are suffering, at least locally. Close monitoring of future developments in the trade will be essential to allow for timely conservation action as and when necessary, and would contribute to our understanding of the ecological and economical implications of small‐scale, non‐food fisheries.

Copyright © 2004 John Wiley & Sons, Ltd.     

Fisheries and trade of seahorses, Hippocampus spp., in southern India

Abstract  Seahorses ( Hippocampus spp. ) are a major commodity fished from the shallow coastal seas of the south coast of India where there is an abundance of sea grasses, sponges and corals. They are in great demand for export as traditional medicines, curios and aquarium fish. Organised fishing and trade of seahorses exists in India along the Palk Bay and Gulf of Mannar coasts. At the Palk Bay coast, seahorses are targeted by divers along with sea cucumbers ( Holothuria spp. ) and gastropods (e.g. Murex spp., Xancus pyrum Hornell). In the Gulf of Mannar, most of the seahorses are landed as bycatch of shrimp trawling. Seahorses are also fished from Kerala as a bycatch of trawling, although no organised fishery and trade exists. Five species of seahorses were identified from the Palk Bay coast, whereas only two species were obtained from Kerala. Most seahorses from India are exported to Singapore, Hong Kong, Malaysia and the United Arab Emirates. The volume of dried seahorse trade from India was estimated to be 9.75 t as derived from catch data in 2001, which was much higher than official statistics of 4.34 t during 2001–2002, suggesting the major part of the exports might be through non-conventional means and goes undeclared. Some aspects of the impact of large-scale fishing and trade on conservation of these seahorses are discussed.     

Harvest,trade and conservation of the Asian arowana Scleropages formosus in Cambodia

• 1. The worldwide trade in aquarium fish is a multi‐billion dollar industry. One of the most popular and expensive species traded is the Asian arowana Scleropages formosus. As a result of over‐harvesting for the aquarium fish trade, S. formosus is now endangered and commercial international trade in the species is prohibited under CITES. Despite this, very little is known about S. formosus in the wild.
• 2. Interviews were conducted with 62 local villagers at four sites in Koh Kong province, south‐west Cambodia, to obtain information on the reproduction, historical and current harvest and trade, and population trends of S. formosus.
• 3. The spawning season of S. formosus in Cambodia begins towards the end of the dry season (March–April) and is approximately 3 months in duration. Each male mouth‐broods an average of 30 juveniles. Harvesters target S. formosus fry and juveniles, and typically kill or frighten brooding males into releasing their offspring in order to harvest them.
• 4. The prices obtained by harvesters for S. formosus has been increasing since collection began, and currently averages $US11–13 per juvenile. After collection, fish are transported through a series of larger towns, most ultimately bound for Thailand. The current number of S. formosus harvested from the wild in Cambodia is almost certainly highly unsustainable, with all respondents indicating that local S. formosus population abundance had declined dramatically in recent years. It is also likely that a number of populations have already become locally extinct.
• 5. Strengthening legislation to protect the species within Cambodia, increasing enforcement of cross‐border trade, and an investigation into alternative low‐impact income generation opportunities for local communities is vital. There is also an urgent need to gather detailed information on the distribution, population abundance and threats facing S. formosus in Cambodia, and in other countries throughout its range.

Copyright © 2008 John Wiley & Sons, Ltd.     

Preservation causes shrinkage in seahorses: implications for biological studies and for managing sustainable trade with minimum size limits

• 1. The implications of shrinkage associated with desiccation and ethanol preservation for seahorses (genus Hippocampus) were investigated using Hippocampus guttulatus (European long‐snouted seahorse) as a model. Specifically, this research addressed the implications of preservation for taxonomy and life history studies and the application of minimum size limits (MSL) for managing seahorse trade.
• 2. In 2004, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) listed all seahorse species on its Appendix II, and recommended a 10 cm MSL as an interim means of ensuring sustainable international trade. Inconsistencies in seahorse measurement methods and repeatability posed challenges for applying the MSL. Moreover, the shrinking effect of desiccation on body length observed in other fish was assumed to be negligible for seahorses because of their high degree of ossification.
• 3. Changes in seahorse sizes were measured following immersion in ethanol and desiccation. H. guttulatus shrank on average by 0.1–2.3% when preserved in ethanol and 3.0–6.4% when dried, depending on the trait measured. Similar trends were observed in a sample of H. kuda (yellow seahorse). Specimen posture during drying, and measurement methods also influenced estimates of size.
• 4. Based on the shrinkage observed, 14–44% of captured seahorses that are dried could shrink to below the recommended MSL, even if all seahorses were longer than the MSL at capture. This demonstrates that small changes in body lengths can have significant implications for trade of species managed with size limits.
• 5. Recommendations are to (1) standardize seahorse measurement methods, (2) consider the effects of preservation and measurement technique on body lengths, and apply appropriate corrections in comparative studies and when developing fisheries management strategies, and (3) adjust size limits at the point of capture to ensure retained seahorses comply with the CITES recommended MSL.

Copyright © 2008 John Wiley & Sons, Ltd.     

Freshwater fishes of Southeast Asia: potential for the aquarium fish trade and conservation issues

SoutheastAsia is an area rich in biodiversity, with a high degree ofendemism in both flora and fauna. Many freshwater fish specieshave been exploited for the ornamental fish trade. As thepopulation in South East Asia increases, vast tracts of forestsare cleared for agricultural, industrial and urbanizationpurposes. To conserve and sustainably exploit the wild fishpopulation, measures should be adopted to protect this naturalresource. Already, several ornamental species have been severelyoverexploited, e.g. bala shark (Balantiocheilos melanopterus),pygmy loach (Botia sidthimunki) and arowana (Scleropagesformosus), but the extirpation of local populations occurs formany reasons, including deforestation, and not just because offishing for the trade. There are also still many species thathave great ornamental fish potential. Wild fish species have alsobeen successfully bred in captivity and conserved, e.g. tigerbarb (Puntius tetrazona), bala shark, pygmy loach and arowana.Other methods of conservation include public education, leavingpristine forests intact and reforestation. The aquarium trade ofthe bala shark, harlequin rasbora (Rasbora heteromorpha), clownloach (Botia macracanthus), arowana and sawfish (Pristismicrodon) is discussed     

Elasmobranch fishing and trade in Sarawak,Malaysia, with implications for management

1. Many shark and ray (elasmobranch) species are threatened with extinction, due to overfishing and commercial trade
2. Sarawak is situated in Malaysian Borneo in the Coral Triangle: a global priority region for elasmobranch conservation. Malaysia is the world’s eighth largest elasmobranch fishing nation, and Sarawak is one of Malaysia’s largest fishing states, yet there are limited species-specific data on catch and trade of elasmobranchs to support conservation and fisheries management decisions.
3. This study presents landing site and market survey data, collected in Sarawak from January 2017 to December 2019. Geographical, temporal and operational trends in volumes of catch and trade are explored; the total volume, value and species composition of Sarawak's local elasmobranch markets is estimated; and simple size-based indicators are used to assess the sustainability of elasmobranch utilization for several conservation-priority and frequently traded species, including Critically Endangered and CITES-listed scalloped hammerhead sharks (Sphyrna lewini) and bottlenose wedgefish (Rhynchobatus australiae).
4. The results conservatively estimate that >26,500 elasmobranchs (~90,000 kg) are locally traded in Sarawak annually, worth ~US$125,000 per year at the market level.
5. Trade is dominated by small to medium-sized coastal requiem sharks (Carcharhinidae) and stingrays (Dasyatidae), with endangered and CITES-listed species making up 26% and 32% of total landings and trade, respectively.
6. High proportions of immature individuals were recorded, with evidence of overfishing for several species, based on simple size-based indicators.
7. Several options are outlined for improving management of elasmobranch fishing and trade in the future, including spatio-temporal closures and live release protocols, which could help to reduce the mortality of critically endangered species and implement CITES. Such measures could have large conservation impacts with limited socio-economic cost, since these species make up <5% of the total value of the elasmobranch market. However, management plans need to be co-designed with full participation of affected coastal communities in order to be ethical and effective.

     

Bycatch in a tropical schooling – penaeid fishery and comparisons with a related, specialised trawl regime

Abstract  The bycatch in a tropical Australian banana prawn, Penaeus merguiensis (de Man), fishery is described and contrasted with the closely related tiger prawn, Penaeus semisulcatus De Haan and Penaeus esculentus Haswell, fishery. Most of the similarity between banana prawn fishery catches was accounted for by three teleost species constituting 51.4% of the total bycatch weight. The bycatch assemblage structure of this fishery was significantly different ( P  <   0.05) from the adjoining tiger prawn fishery. The banana prawn fishery had a higher mean bycatch catch rate from shorter duration trawls, but lower estimated total annual bycatch (1502 t yr⁻¹) than the longer duration trawls of the tiger prawn fishery (20 073 t yr⁻¹). This study provides new data for quantifying bycatch and improving the accuracy of quantitative risk assessments currently being used to demonstrate sustainability of bycatch populations. The information will be incorporated into collaborative development of a long-term monitoring programme.     

Biodiversity,ecology, fisheries,and use and trade of Tetraodontiformes fishes reveal their socio‐ecological significance along the tropical Brazilian continental shelf

1. Tetraodontiformes fishes play a critical role in benthic and demersal communities and are facing threats due to anthropogenic impacts and climate change. However, they are poorly studied worldwide. To improve knowledge on the socio‐ecological significance and conservation of Tetraodontiformes a review of literature addressing the diversity, ecology, use and trade, conservation, and main threats of Tetraodontiformes combined with a comprehensive in situ dataset from two broad‐range multidisciplinary oceanographic surveys performed along the Tropical Brazilian Continental Shelf was undertaken.
2. Twenty‐nine species were identified, being primarily found on coral reefs and algal ecosystems. At these habitats, tetraodontids present highly diversified trophic categories and might play an important role by balancing the marine food web
3. Coral reef ecosystems, especially those near to the shelf break, seem to be the most important areas of Tetraodontiformes fishes, concentrating the highest values of species richness, relative abundance and the uncommon and Near Threatened species.
4. Ninety per cent of species are commonly caught as bycatch, being also used in the ornamental trade (69%) and as food (52%), serving as an important source of income for artisanal local fisheries.
5. Tetraodontiformes are threatened by unregulated fisheries, overexploitation, bycatch, and habitat loss due to coral reef degradation and the potential effects of climate change. These factors are more broadly impacting global biodiversity, food security, and other related ecosystem functions upon which humans and many other organisms rely.
6. We recommend the following steps that could improve the conservation of Tetraodontiformes along the tropical Brazilian Continental shelf and elsewhere: (i) data collection of the commercial, incidental, ornamental and recreational catches; (ii) improvement of the current legislation directed at the marine ornamental harvesting; (iii) increase efforts focused on the education and conservation awareness in coastal tourism and communities; and, most important, (iv) creation of marine reserves networks in priority areas of conservation, protecting either the species and key habitats for its survival.

     

Polyculture of Freshwater Angelfish Pterophyllum scalare and Pacific white shrimp Litopenaeus vannamei in low‐salinity water

In this study, we evaluated the production potential of the polyculture of Freshwater Angelfish (Pterophyllum scalare, Cichlidae) and Pacific white shrimp (Litopenaeus vannamei). Two experimental trials were set up. The first trial entailed the use of a randomized design to investigate three treatments options: angelfish monoculture, shrimp monoculture, and fish and shrimp polyculture in 12 experimental 15 m² ponds. In the second trial, we investigated two treatments (polyculture of caged fish and uncaged fish) in 10 experimental units. In trial 1, polyculture negatively affected fish growth and survival. However, fish did not affect shrimp growth and the greatest profit was achieved in polyculture. In trial 2, caging fish improve the growth of both fish and shrimp. An economic analysis showed the greatest profit and benefit cost ratio for caged fish compared with uncaged fish. We conclude that growing P. scalare and L. vannamei together is a better strategy than shrimp monoculture in low‐salinity water. The use of caged fish in such a polyculture operation would enhance productivity and profitability.     

Effect of photoperiod and tank colour on growth and survival of pelagic‐phase seahorse Hippocampus reidi

The effect of photoperiod and tank colour on the survival and growth of juvenile seahorse Hippocampus reidi was investigated in the first 15 days after release (DAR). In the first experiment, newly released seahorses were exposed to six photoperiods – 6 h of light (L):18 h of darkness (D), 10L:14D, 12L:12D, 14L:10D, 18L:6D and 24L:0D. In the second experiment, juveniles were kept in tanks of different background colours – blue, white, black, clear and red. No significant differences were observed in the growth and survival among seahorse subjected to 10–24 h of light (P > 0.05). At the end of 15 DAR, fish exposed to 6L:18D showed lower growth in height and weight compared to other treatments (13.8 mm vs. 20.0–22.2 mm and 13.4 mg vs. 37.2–43.2 mg respectively) and lower survival (80% vs. 88–95% respectively). Tank colour did not affect growth and survival of juveniles up to 15 DAR.     

Opportunities and challenges for analysis of wildlife trade using CITES data – seahorses as a case study

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Developing a landscape‐scale,multi‐species,and cost‐efficient conservation strategy for imperilled aquatic species in the Upper Tennessee River Basin,USA

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Diseases of captive yellow seahorse Hippocampus kuda Bleeker,pot‐bellied seahorse Hippocampus abdominalis Lesson and weedy seadragon Phyllopteryx taeniolatus (Lacépède)

Seahorses, pipefish and seadragons are fish of the Family Syngnathidae. From 1998 to 2010, 172 syngnathid cases from the Toronto Zoo were submitted for post‐mortem diagnostics and retrospectively examined. Among the submitted species were yellow seahorses Hippocampus kuda Bleeker (n = 133), pot‐bellied seahorses Hippocampus abdominalis Lesson (n = 35) and weedy seadragons Phyllopteryx taeniolatus (Lacépède; n = 4). The three most common causes of morbidity and mortality in this population were bacterial dermatitis, bilaterally symmetrical myopathy and mycobacteriosis, accounting for 24%, 17% and 15% of cases, respectively. Inflammatory processes were the most common diagnoses, present in 117 cases. Seven neoplasms were diagnosed, environmental aetiologies were identified in 46 cases, and two congenital defects were identified.     

Volume and Value of Marine Ornamentals Collected in Florida, 1990–98

The marine life fishing industry in Florida is defined by the state as the non-lethal harvest of marine plants, finfish, and invertebrates that are sold live for commercial purposes (primarily into the saltwater aquarium industry). Approximately 330 different species of finfish and invertebrates are harvested by marine life collectors in Florida, including 180 species of finfish and 150 species of invertebrates and plants. In 1998, the total dockside value of these species was approximately US$1.9 million. The industry is highly regulated via limits on gear, handling methods, harvest sizes, and trip/bag/possession limits. Entry into the industry has been recently curtailed by the implementation of a moratorium on marine life endorsements. The total number of licensed harvesters exceeded 700 in 1998. Approximately 70 wholesales buyers also participated in the market during 1998. The majority of the dockside value is generated in south Florida, with the majority of the remaining value accruing from the region including and north of Tampa Bay. Over 80% of the total value associated with both finfish and invertebrates is generated by only 10 species within each group. Dockside prices vary considerably among the various species landed, with those landed in greater volumes exhibiting the lower prices.     

Designation and management of large‐scale MPAs drawing on the experiences of CCAMLR

With the adoption of the United Nations Law of the Sea came the need for effective worldwide control of marine fisheries. Initially centred on single species, the tasks have extended to ecosystem‐based management through the concept of marine‐protected areas into habitats and biodiversity. These diverse requirements have placed enhanced responsibilities on fisheries management organizations. Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has successfully developed effective management measures for the Southern Ocean but has encountered difficulties in establishing marine‐protected areas. Key to the success of CCAMLR has been the establishment of conservation measures on clearly defined topics through decision making by consensus. It is argued that the problems that CCAMLR has encountered in establishing marine‐protected areas centre on the range of features, in terms of stakeholder interests, to be afforded protection allied to problems with the consensus process. In this paper, the approaches of CCAMLR in converting the conceptual framework of treaty language into practical management measures using consensus are discussed in relation to the manner in which marine‐protected areas might be established within other fisheries management organizations. It is concluded that the most effective approach is as a composite of strictly focussed conservation measures the sum of which cover all facets of a marine‐protected area. This approach has the further advantage that individual components can be changed without opening the whole legal instrument to re‐negotiation.     

Role of large‐ and fine‐scale variables in predicting catch rates of larval Pacific lamprey in the Willamette Basin,Oregon

Pacific lamprey Entosphenus tridentatus is an anadromous fish native to the Pacific Northwest of the USA. That has declined substantially over the last 40 years. Effective conservation of this species will require an understanding of the habitat requirements for each life history stage. Because its life cycle contains extended freshwater rearing (3–8 years), the larval stage may be a critical factor limiting abundance of Pacific lamprey. The objective of our study was to estimate the influence of barriers and habitat characteristics on the catch‐per‐unit‐effort (CPUE) of larval Pacific lamprey in the Willamette River Basin, Oregon, USA. We sampled lampreys at multiple locations in wadeable streams throughout the basin in 2011–13 and used an information theoretic approach to examine the relative influence of fine‐ and large‐scale predictors of CPUE. Pacific lamprey was observed across the basin, but its relative abundance appeared to be limited by the presence of natural and artificial barriers in some sub‐basins. Lower velocity habitats such as off‐channel areas and pools contained higher densities of larval lamprey; mean Pacific lamprey CPUE in off‐channel habitats was 4 and 32 times greater than in pools and riffles respectively. Restoration and conservation strategies that improve fish passage, enhance natural hydrologic and depositional processes and increase habitat heterogeneity will likely benefit larval Pacific lamprey.     

The use of preserved copepods in sea bream small‐scale culture: biometric,biochemical and molecular implications

Considering the well‐known problems arising from the use of rotifers and Artemia as live prey in larval rearing in terms of fatty acid deficiencies, the aim of this study was to evaluate a partial or complete replacement of traditional live prey with preserved copepods during the larviculture of gilthead sea bream (Sparus aurata). Sea bream larvae were randomly divided into 4 experimental groups in triplicates: group A larvae (control) fed rotifers followed by Artemia nauplii; group B fed a combined diet (50%) of rotifers–Artemia and preserved copepods; group C fed rotifers followed by preserved copepods; and group D fed preserved copepods solely. Survival and biometric data were analysed together with major molecular biomarkers involved in growth, lipid metabolism and appetite. Moreover, fatty acid content of prey and larvae was also analysed. At the end of 40 days treatment, a stress test, on the remaining larvae, was performed to evaluate the effects of different diets on stress response. Data obtained evidenced a positive effect of cofeeding preserved copepods during sea bream larviculture. Higher survival and growth were achieved in group B (fed combined diet) larvae respect to control. In addition, preserved copepods cofeeding was able to positively modulate genes involved in fish growth, lipid metabolism, stress response and appetite regulation.     

Growth performances for monoculture and polyculture of hatchery‐reared juvenile spotted babylon,Babylonia areolata Link, 1807, in large‐scale earthen ponds

This study was conducted to determine the feasibility of growing out hatchery‐reared spotted babylon juvenile (Babylonia areolata) in earthen ponds. The growth, survival and water quality for monoculture of spotted babylon were compared with the two polyculture trials with sea bass (Lates calcarifer) or milkfish (Chanos chanos). This study provided good results for growth and survival of spotted babylon in earthen ponds. The mean body weight gain of snails held in the monoculture was 5.39±0.08 g, and 4.07±0.16 and 4.25±0.11 g for those held in the polyculture with sea bass or milkfish respectively. Food conversion ratios (FCR) were 2.69, 2.96 and 2.71 for snails held in the monoculture and polyculture with sea bass and milkfish, respectively, and the final survival rates were 84.94%, 74.30% and 81.20% respectively. There were no significant differences in each parameter of water quality among the treatments but significant differences among the culture period were present (P<0.05). Salinity and total alkalinity showed the greatest changes during the culture period for all treatments. Seawater temperature, pH, dissolved oxygen, nitrite–nitrogen and ammonia–nitrogen gradually changed over the culture period for all the treatments. The present study indicated the technical feasibility for monoculture and polyculture of B. areolata to marketable sizes in earthen ponds.