Eric Gilman

Seabird Bycatch in Pelagic Longline Fisheries Is Grossly Underestimated when Using Only Haul Data

Hundreds of thousands of seabirds are killed each year as bycatch in longline fisheries. Seabirds are predominantly caught during line setting but bycatch is generally recorded during line hauling, many hours after birds are caught. Bird loss during this interval may lead to inaccurate bycatch information. In this 15 year study, seabird bycatch was recorded during both line setting and line hauling from four fishing regions: Indian Ocean, Southern Ocean, Coral Sea and central Pacific Ocean. Over 43,000 albatrosses, petrels and skuas representing over 25 species were counted during line setting of which almost 6,000 seabirds attempted to take the bait. Bait-taking interactions were placed into one of four categories. (i) The majority (57%) of bait-taking attempts were “unsuccessful” involving seabirds that did not take the bait nor get caught or hooked. (ii) One-third of attempts were “successful” with seabirds removing the bait while not getting caught. (iii) One-hundred and seventy-six seabirds (3% of attempts) were observed being “caught” during line setting, with three albatross species – Laysan (Phoebastria immutabilis), black-footed (P. nigripes) and black-browed (Thalassarche melanophrys)– dominating this category. However, of these, only 85 (48%) seabird carcasses were retrieved during line hauling. Most caught seabirds were hooked through the bill. (iv) The remainder of seabird-bait interactions (7%) was not clearly observed, but likely involved more “caught” seabirds. Bait taking attempts and percentage outcome (e.g. successful, caught) varied between seabird species and was not always related to species abundance around fishing vessels. Using only haul data to calculate seabird bycatch grossly underestimates actual bycatch levels, with the level of seabird bycatch from pelagic longline fishing possibly double what was previously thought.

Comparison of three seabird bycatch avoidance methods in Hawaii-based pelagic longline fisheries

Capture in longline fisheries is a critical threat to most albatross and large petrel species. Blackfooted Phoebastria nigripes and Laysan P. immutabilis albatrosses are the predominant seabird species incidentally caught in Hawaii longline fisheries. This study reports results of a trial in the Hawaii pelagic longline tuna and swordfish fisheries comparing four experimental treatments’ seabird capture rates and commercial viability. Two research fishing trips were conducted between 1 April and 17 May 2003 on a Hawaii-based pelagic longline vessel, at traditional fishing grounds south of the Northwestern Hawaiian Islands, between 21° 41′N and 25° 08′N, 173° 58′W and 167° 43′W.

Efficacy of alternative low-cost approaches to mangrove restoration, American Samoa

Three mangrove restoration methods were tested at Nu’uuli, Tutuila Island, American Samoa. Since clearing 27 years ago converted the mangrove into a mudflat, the ecosystem was sufficiently altered that it could not self-correct; the ecosystem showed no natural regrowth despite an ample supply of propagules. While several years of monitoring may ultimately be required to determine the project’s success, and several decades could be required to fully return the full suite of functions, the project’s low-cost, nontechnical restoration techniques, using readily available materials, have proven to be modestly successful, with 38% sapling survival after six months. Several years of monitoring will be necessary to determine if the restoration site’s small elevation deficit relative to a reference site ultimately requires modifying the site’s physical structure to correct the hydrology. Direct community participation in the project was critical to reduce the risk of human disturbance of the restoration site. One year project costs were about USD

Designing criteria suites to identify discrete and networked sites of high value across manifestations of biodiversity

2,150 or USD

Risk Factors for Seabird Bycatch in a Pelagic Longline Tuna Fishery.

13,030 ha−1. Labor comprised 84% of expenses; replicating the restoration project in developing countries would cost less due to lower wage levels. Six months after initial restoration activities, there was a highly significant difference betweenBruguiera gymnorrhiza andRhizophora mangle sapling survival, with 21% and 45% of the original 42R. mangle and 95B. gymnorrhiza saplings remaining, respectively. The lowerR. mangle survival may have resulted from an unavoidable need to source saplings from an area with different environmental conditions than the restoration site. Saplings were transplanted into tires filled with sediment as a simple, low-cost method to raise the elevation of the sediment surface. Saplings were also transplanted adjacent to rebar and without any support mechanism. There was no significant difference in sapling survival by treatment for individual or combined species. The restoration project is a model for the community-based, simple, low-cost approaches to ecological restoration needed in the region. Pilot projects using similar techniques may be worth pursuing at the other 15 Pacific Island countries and territories where mangroves are indigenous.

A method to investigate wetland mitigation banking for Saipan, Commonwealth of the Northern Mariana Islands

Suites of criteria specifying ecological, biological, social, economic, and governance properties enable the systematic identification of sites and networks of high biodiversity value, and can support balancing ecological and socioeconomic objectives of biodiversity conservation in terrestrial and marine spatial planning. We describe designs of suites of ecological, governance and socioeconomic criteria to comprehensively cover manifestations of biodiversity, from genotypes to biomes; compensate for taxonomic and spatial gaps in available datasets; balance biases resulting from conventionally-employed narrow criteria suites focusing on rare, endemic and threatened species; plan for climate change effects on biodiversity; and optimize the ecological and administrative networking of sites. Representativeness, replication, ecological connectivity, size, and refugia are identified as minimum ecological properties of site networks. Through inclusion of a criterion for phylogenetic distinctiveness, criteria suites identify sites important for maintaining evolutionary processes. Criteria for focal species are needed to overcome data gaps and address limitations in knowledge of factors responsible for maintaining ecosystem integrity.

Ecological data from observer programmes underpin ecosystem-based fisheries management

Capture in global pelagic longline fisheries threatens the viability of some seabird populations. The Hawaii longline tuna fishery annually catches hundreds of seabirds, primarily Laysan (Phoebastria immutabilis) and black-footed (P. nigripes) albatrosses. Since seabird regulations were introduced in 2001, the seabird catch rate has declined 74%. However, over the past decade, seabird catch levels significantly increased due to significant increasing trends in both effort and nominal seabird catch rates. We modelled observer data using a spatio-temporal generalized additive mixed model with zero-inflated Poisson likelihood to determine the significance of the effect of various risk factors on the seabird catch rate. The seabird catch rate significantly increased as annual mean multivariate ENSO index values increased, suggesting that decreasing ocean productivity observed in recent years in the central north Pacific may have contributed to the increasing trend in nominal seabird catch rate. A significant increasing trend in number of albatrosses attending vessels, possibly linked to declining regional ocean productivity and increasing absolute abundance of black-footed albatrosses, may also have contributed to the increasing nominal seabird catch rate. Largest opportunities for reductions are through augmented efficacy of seabird bycatch mitigation north of 23° N where mitigation methods are required and during setting instead of during hauling. Both side vs. stern setting, and blue-dyed vs. untreated bait significantly reduced the seabird catch rate. Of two options for meeting regulatory requirements, side setting had a significantly lower seabird catch rate than blue-dyed bait. There was significant spatio-temporal and seasonal variation in the risk of seabird capture with highest catch rates in April and May and to the northwest of the main Hawaiian Islands.

Mitigating bycatch in tuna fisheries

Abstract The Commonwealth of the Northern Mariana Islands (CNMI) government is considering developing a wetlands mitigation bank on the island of Saipan. The goals of developing the bank are to maximize cost effectiveness of compensatory wetland mitigation, streamline the wetland regulatory framework, and minimize environmental impacts from compensatory wetland mitigation. This article describes the method being employed by the Joint Federal/CNMI Environmental Working Group (Group) to make a recommendation to Governor Froilan C. Tenorio concerning whether the CNMI should establish a Saipan wetland mitigation bank. The Groups method has three components: (1) considering alternative methods to streamline the wetland regulatory framework and enhance the protection of wetlands that may be more suitable to the Saipan context than a wetland mitigation bank; (2) conducting a cost-benefit analysis of potential environmental, economic, and regulatory outcomes of using a mitigation bank; and, (3) analysing regulatory, economic, and ecological risks associated with establishing and using a Saipan bank. A description of the CNMIs wetland resources and the wetland regulatory framework justifies the method being employed by the Group. Federal and CNMI regulators of Saipans wetlands currently do not possess the technical ability to ensure that there is no net loss of all wetland functions, but are managing Saipans wetlands solely based on concerns with impacts to bird habitat. Thus, the siting and design of a Saipan bank would currently only be based on managing wetlands according to habitat concerns, and use of the bank would not necessarily prevent a net loss of wetland quality. The Group recognizes the need for a wetland assessment method that can account for the full suite of CNMI wetland functions in order for a Saipan bank to fulfill the Federal mandate for no net loss of wetland quality or quantity. The CNMIs tropical freshwater wetland ecology and level of technical expertise in wetland science require a specific bank design, monitoring and maintenance activities, and enabling instrument in order to be successful in the CNMI context. Fortunately, Federal guidance on the establishment, use, and administration of wetland mitigation banks is flexible enough to enable the CNMI to establish a Saipan bank that fits their unique environmental and social context. Federal guidance appears to unconditionally encourage the establishment and use of banks. However, a wetland mitigation bank may not be appropriate for the local environmental, regulatory, and economic context of a specific city or island. Banking is not a definite panacea to streamline the wetland regulatory framework and enhance wetland protection, and can just as likely worsen problems as remedy them depending on the local context. It is therefore important to investigate economic, regulatory, and environmental risks, costs, and benefits, and to consider all available methods to improve wetlands management as described in this article. This article is a working paper of the Joint Federal/CNMI Environmental Working Group.

Effects of pelagic longline hook size on species- and size-selectivity and survival

Ecological data from observer programmes underpin ecosystem-based fisheries management Eric Gilman*, Mariska Weijerman, and Petri Suuronen Hawaii Pacific University, Pelagic Ecosystems Research Group, 3661 Loulu Street, Honolulu, HI, USA Pacific Islands Fisheries Science Center, NOAA Fisheries, 1845 Wasp Boulevard, Building 176, Honolulu, HI, USA Fisheries and Aquaculture Department, Food and Agriculture Organization of the United Nations (FAO), Viale delle Terme di Caracalla, Rome, Italy *Corresponding author: tel: þ1.808.888.9440; e-mail: fisheriesresearchgroup@gmail.com

Scenarios for Global Biodiversity in the 21st Century

Monitoring and managing fisheries bycatch is increasingly recognized as a critical component of robust fisheries management frameworks. This review, addressing this subject, begins by defining bycatch and analyzing the reasons it happens, from accidental to intentional discarding. It identifies the most common species composing bycatch of the main tuna fisheries using purse seine and longline gear. Considerations of options available to estimate bycatch, their potential biases and uncertainties, and ways to address these issues are discussed. The formulas used to estimate bycatch also point to the options to reduce them, lowering bycatch per unit of effort or lowering effort itself. It shows that a mean can be reduced by reducing all its component figures, or by eliminating the high values at the extreme of the distribution (i.e., where a small proportion of events causes a large proportion of the problem), a common issue in bycatch. A generic strategy is described that can be applied to all gears and fisheries, and it is then described for the fisheries of interest, showing examples of its application. These cover many mitigation actions based on gear and operational changes. Management options aiming at reducing bycatch are also mentioned. A detailed description of the ways the strategy has been implemented for purse seiners and longliners is provided. Finally, market strategies, education and awareness of stakeholders, mainly fishers, and some potential future developments are briefly described.