Heather J. Koldewey

Conservation and management of seahorses and other Syngnathidae

This article analyses the pressures on seahorses and explores conservation responses. It focuses on seahorses (Hippocampus spp.) but also considers pipefishes and seadragons, especially where they can fill gaps in seahorse knowledge. The charisma of many syngnathids can make them good flagship species for threats and solutions in marine conservation. The article combines a synthesis of published literature with new data on the trade in seahorses for traditional medicine, aquarium display and curiosities. Most traded seahorses come from trawl by-catch, although seahorses are also targeted. The total extraction is large, tens of millions of animals annually, and unsustainable. A first review of the effect of habitat change on syngnathids raises many questions, while suggesting that some species may cope better than others. The combination of pressures means that many species of syngnathid are now included in the IUCN Red List of Threatened Species or national equivalents. In addition, seahorse exports from 175 countries are limited to sustainable levels under the Convention on International Trade in Endangered Species (CITES) of Wild Fauna and Flora. Possible conservation measures include marine protected areas, fisheries management, select aquaculture ventures, trade regulation, improved governance (particularly) and consumer engagement.

The Risks of Assisted Colonization

There is a growing debate over whether species should be translocated outside their historic ranges to deal with extinction risks as habitats shift due to climate change. This idea of taking preemptive action to avert predicted extinction risks has been given emphasis by the recent International Union for Conservation of Nature (IUCN) assessment of species susceptibility to climate-change impacts (Foden et al. 2008), prompting suggestions that “more aggressive measures, such as so-called ‘assisted migration’” be considered (Marris 2008). Hoegh-Guldberg et al. (2008) provide a decision framework for identifying scenarios in which what they term “assisted colonization” (AC) is justified. We see problems with the impact of these articles, despite their conservative approach. First, there are current international translocation guidelines (IUCN 1998) that provide a strong rationale against the early adoption of AC as a conservation tool. The Reintroduction Specialist Group (RSG) was created in 1988 to address the proliferation of ill-conceived translocations that had been taking place, including many releases of species outside historic ranges (Stanley Price & Soorae 2003). The RSG formulated the guidelines for translocation planning to ensure that conservation benefits accrue. “Benign introduction” (BI)—the translocation of species to suitable habitat outside their historic range as a conservation measure—was considered appropriate only when there was no habitat left within the original species range (IUCN 1998). Although AC appears to fall within the definition of BI, the two differ in that AC aims proactively to establish species outside their historic range to preempt predicted climate-driven changes in habitat suitability. Calls to take proactive conservation measures need to consider that there are currently huge uncertainties involved, not only in climatechange predictions and consequent species responses (Araújo et al. 2005; Hulme 2005; Sekercioglu et al. 2008) but also in our understanding of the habitat requirements of species (Stamps & Swaisgood 2007) and the effects of translocations on ecosystem function (Armstrong & Seddon 2008). At a recent conference (First International Wildlife Reintroduction Conference, Lincoln Park Zoo, Chicago, Illinois,April2008, http://www. reintroduction.org/), RSG members discussed climate-change implications for translocations, acknowledging the need for the integration of reintroduction biology and restoration ecology, and the updating of translocation guidelines to consider issues such as the mitigation of climate-driven habitat change and overcoming barriers to natural dispersal of species. Given current uncertainty, however, there is substantial risk that prematurely embracing the undeniably sexy AC concept will initiate a new era of ill-conceived species translocations. Philip J. Seddon,∗ Doug P. Armstrong,† Pritpal Soorae,‡ Frederic Launay,§ Sally Walker,∗∗ Carlos R. Ruiz-Miranda,†† Sanjay Molur,∗∗ Heather Koldewey,‡‡ and Devra G. Kleiman§§ ∗RSG Bird Section Chair, Department of Zoology, University of Otago, Dunedin, New Zealand, email philip.seddon@stonebow. otago.ac.nz †RSG Australasia Chair, Massey University, Palmerston North, New Zealand ‡RSG Programme Officer, Environment Agency, Abu Dhabi, United Arab Emirates §RSG Chair, Environment Agency, Abu Dhabi, United Arab Emirates ∗∗RSG South Asia co-Chair, Zoo Outreach, Coimbatore, India ††RSG Meso-South America Chair, Environmental Sciences Laboratory, Universidade Estadual do Norte Fluminense, Rio de Janeiro, Brazil ‡‡RSG Fish Section Chair, Zoological Society of London, London, United Kingdom §§RSG North America Chair, Zoo-Logic, Chevy Chase, MD 20815, U.S.A.

The Interaction between Seaweed Farming as an Alternative Occupation and Fisher Numbers in the Central Philippines

Alternative occupations are frequently promoted as a means to reduce the number of people exploiting declining fisheries. However, there is little evidence that alternative occupations reduce fisher numbers. Seaweed farming is frequently promoted as a lucrative alternative occupation for artisanal fishers in Southeast Asia. We examined how the introduction of seaweed farming has affected village-level changes in the number of fishers on Danajon Bank, central Philippines, where unsustainable fishing has led to declining fishery yields. To determine how fisher numbers had changed since seaweed farming started, we interviewed the heads of household from 300 households in 10 villages to examine their perceptions of how fisher numbers had changed in their village and the reasons they associated with these changes. We then asked key informants (people with detailed knowledge of village members) to estimate fisher numbers in these villages before seaweed farming began and at the time of the survey. We compared the results of how fisher numbers had changed in each village with the wealth, education, seaweed farm sizes, and other attributes of households in these villages, which we collected through interviews, and with village-level factors such as distance to markets. We also asked people why they either continued to engage in or ceased fishing. In four villages, respondents thought seaweed farming and low fish catches had reduced fisher numbers, at least temporarily. In one of these villages, there was a recent return to fishing due to declines in the price of seaweed and increased theft of seaweed. In another four villages, fisher numbers increased as human population increased, despite the widespread uptake of seaweed farming. Seaweed farming failed for technical reasons in two other villages. Our results suggest seaweed farming has reduced fisher numbers in some villages, a result that may be correlated with socioeconomic status, but the heterogeneity of outcomes is consistent with suggestions that alternative occupations are not a substitute for more direct forms of resource management.

Potential benefits to fisheries and biodiversity of the Chagos Archipelago/British Indian Ocean Territory as a no-take marine reserve.

On 1st April 2010, the British Government announced designation of the British Indian Ocean Territory--or Chagos Archipelago--as the worlds largest marine protected area (MPA). This near pristine ocean ecosystem now represents 16% of the worlds fully protected coral reef, 60% of the worlds no-take protected areas and an uncontaminated reference site for ecological studies. In addition these gains for biodiversity conservation, the Chagos/BIOT MPA also offers subsidiary opportunities to act as a fisheries management tool for the western Indian Ocean, considering its size and location. While the benefits of MPAs for coral-reef dwelling species are established, there is uncertainty about their effects on pelagic migratory species. This paper reviews the increasing body of evidence to demonstrate that positive, measurable reserve effects exist for pelagic populations and that migratory species can benefit from no-take marine reserves.

Avoiding Empty Ocean Commitments at Rio+20

To improve sustainability of ocean ecosystems, implementation of existing commitments should be prioritized. The principles of sustainable management of marine capture fisheries and the protection of biodiversity are established by the United Nations Convention on the Law of the Sea (UNCLOS) and its implementing agreement (1). Building on these, Agenda 21, released after the UN “Earth Summit” in 1992 in Rio de Janeiro, and the Johannesburg Plan of Implementation (JPOI) from the 2002 summit, set quantitative and qualitative targets relating to the marine environment (see the table). Unfortunately, implementation of many of these commitments has been difficult, ineffective, or practically nonexistent.

Policy challenges and approaches for the conservation of mangrove forests in Southeast Asia

Many drivers of mangrove forest loss operate over large scales and are most effectively addressed by policy interventions. However, conflicting or unclear policy objectives exist at multiple tiers of government, resulting in contradictory management decisions. To address this, we considered four approaches that are being used increasingly or could be deployed in Southeast Asia to ensure sustainable livelihoods and biodiversity conservation. First, a stronger incorporation of mangroves into marine protected areas (that currently focus largely on reefs and fisheries) could resolve some policy conflicts and ensure that mangroves do not fall through a policy gap. Second, examples of community and government comanagement exist, but achieving comanagement at scale will be important in reconciling stakeholders and addressing conflicting policy objectives. Third, private-sector initiatives could protect mangroves through existing and novel mechanisms in degraded areas and areas under future threat. Finally, payments for ecosystem services (PES) hold great promise for mangrove conservation, with carbon PES schemes (known as blue carbon) attracting attention. Although barriers remain to the implementation of PES, the potential to implement them at multiple scales exists. Closing the gap between mangrove conservation policies and action is crucial to the improved protection and management of this imperiled coastal ecosystem and to the livelihoods that depend on them.

Rehabilitating mangrove ecosystem services: A case study on the relative benefits of abandoned pond reversion from Panay Island, Philippines.

Mangroves provide vital climate change mitigation and adaptation (CCMA) ecosystem services (ES), yet have suffered extensive tropics-wide declines. To mitigate losses, rehabilitation is high on the conservation agenda. However, the relative functionality and ES delivery of rehabilitated mangroves in different intertidal locations is rarely assessed. In a case study from Panay Island, Philippines, using field- and satellite-derived methods, we assess carbon stocks and coastal protection potential of rehabilitated low-intertidal seafront and mid- to upper-intertidal abandoned (leased) fishpond areas, against reference natural mangroves. Due to large sizes and appropriate site conditions, targeted abandoned fishpond reversion to former mangrove was found to be favourable for enhancing CCMA in the coastal zone. In a municipality-specific case study, 96.7% of abandoned fishponds with high potential for effective greenbelt rehabilitation had favourable tenure status for reversion. These findings have implications for coastal zone management in Asia in the face of climate change.

Partial fin-clipping as an effective tool for tissue sampling seahorses, Hippocampus spp.

Partial fin-clipping is a non-lethal sampling technique commonly used to sample tissue for molecular genetic studies of fish. The effect of this technique was tested on seahorses ( Hippocampus spp.) as they have several peculiar biological characteristics when compared with other fish and are on the IUCN Red List of Threatened Species . Partial fin-clipping of the seahorse dorsal fin was evaluated on Hippocampus kuda . The fish were assessed for short-term effects (fin re-growth time) as well as the longer term effects (growth and mortality) of partial fin clipping over a four month period. Total fin re-growth occurred between 2 and 4 weeks with no significant difference observed in the fin re-growth time between sexes. There was no significant difference between the mortality rate/growth rate of clipped versus unclipped seahorses. Results indicate partial fin-clipping has no significant effect on seahorses, and should be considered as a useful method for tissue sampling.

High prevalence of obligate coral-dwelling decapods on dead corals in the Chagos Archipelago, central Indian Ocean

Small and cryptic organisms that live within the interstices of reef habitats contribute greatly to coral reef biodiversity, but are poorly studied. Many species of cryptofauna have seemingly obligate associations with live coral and are therefore considered to be very vulnerable to coral mortality. Here we report the unanticipated prevalence of obligate coral-dwelling decapod crustaceans on dead colonies of branching corals in the Chagos Archipelago (British Indian Ocean Territory) in the central Indian Ocean. A total of 205 obligate coral-dwelling decapods, including Trapezia crabs, were recorded from 43 (out of 54) dead coral colonies of Acropora and Pocillopora collected across five different atolls. Trapezia individuals found on dead corals were mainly juveniles, and the few adults were almost exclusively male. Among the shrimps (Pontoniinae), however, it was predominantly adult females found on dead corals. Obligate coral-dwelling species that typically occur only on live Pocillopora hosts (e.g., Trapezia spp.) were recorded on dead Acropora. These findings suggests that these obligate coral-dwelling decapods are not simply persisting on coral hosts that have died, but may be explicitly recruiting to or moving to dead coral hosts at certain stages in their life cycle. Variation in the abundance of live coral among sites had no affect on the presence or abundance of obligate coral-dwelling decapods on dead corals. This study shows that habitat associations of obligate coral-dwelling organisms, and their reliance on different habitat types, are complex and further work is required to establish their vulnerability to widespread habitat degradation on coral reefs.

Serial monogamy in the European long-snouted seahorse Hippocampus guttulatus

Seahorses (Hippocampus spp.) are non-sex-role-reversed members of the Syngnathidae family that provide extensive brood care. Previous studies of seahorses have revealed monogamy within a single brood, but their longer term mating system had not been comprehensively evaluated. The parental contribution to 29 wild-born broods of Hippocampus guttulatus, sampled from six Portuguese populations with differing seahorse densities and sex ratios, was assessed using microsatellite DNA markers. To assess the longer term genetic mating system of this species parentage was determined in eleven broods sampled from a captive population over two breeding seasons. Genetic data suggest that this socially polygamous seahorse is serially monogamous across breeding seasons, i.e. monogamous within a season but may switch mates between seasons, and that differing population densities and sex ratios do not affect the mating system.