Equatorial populations of marine species are predicted to be most impacted by global warming because they could be adapted to a narrow range of temperatures in their local environment. We ...investigated the thermal range at which aerobic metabolic performance is optimum in equatorial populations of coral reef fish in northern Papua New Guinea. Four species of damselfishes and two species of cardinal fishes were held for 14 days at 29, 31, 33, and 34 °C, which incorporated their existing thermal range (29–31 °C) as well as projected increases in ocean surface temperatures of up to 3 °C by the end of this century. Resting and maximum oxygen consumption rates were measured for each species at each temperature and used to calculate the thermal reaction norm of aerobic scope. Our results indicate that one of the six species, Chromis atripectoralis, is already living above its thermal optimum of 29 °C. The other five species appeared to be living close to their thermal optima (ca. 31 °C). Aerobic scope was significantly reduced in all species, and approached zero for two species at 3 °C above current‐day temperatures. One species was unable to survive even short‐term exposure to 34 °C. Our results indicate that low‐latitude reef fish populations are living close to their thermal optima and may be more sensitive to ocean warming than higher‐latitude populations. Even relatively small temperature increases (2–3 °C) could result in population declines and potentially redistribution of equatorial species to higher latitudes if adaptation cannot keep pace.
A major difficulty in managing wildlife trade is the reliance on trade data (rather than capture data) to monitor exploitation of wild populations. Collected organisms that die or are rejected before ...a point of sale often go unreported. For the global marine aquarium trade, identifying the loss of collected fish from rejection, prior to export, is a first step in assessing true collection levels. This study takes a detailed look at fish rejections by buyers before export using the Papua New Guinea marine aquarium fishery as a case study. Utilizing collection invoices detailing the species and quantity of fish (Actinopteri and Elasmobranchii) accepted or rejected by the exporting company it was determined that, over a six month period, 24.2% of the total fish catch reported (n = 13,886) was rejected. Of the ten most collected fish families, rejection frequency was highest for the Apogonidae (54.2%), Chaetodontidae (26.3%), and Acanthuridae (18.2%) and lowest for Labridae (6.6%) and Hemiscylliidae (0.7%). The most frequently cited reasons for rejection were fin damage (45.6% of cases), undersized fish (21.8%), and fish deemed too thin (11.1%). Despite fishers receiving feedback on invoices explaining rejections, there was no improvement in rejection frequencies over time (r = -0.33, P = 0.15) with weekly rejection frequencies being highly inconsistent (range: 2.8% to 79.4%; s = 16.3%). These findings suggest that export/import statistics can greatly underestimate collection for the marine aquarium trade as additional factors such as fisher discards, escapees, post-collection mortalities, and unregulated domestic trade would further contribute to this disparity.
Sustainable utilization of marine taxa is critical for maximizing social and economic goals of livelihood development within the Indo-Pacific. Yet, despite an increasing importance of shellcraft as a ...livelihood activity within the Indo-Pacific, information on the taxa utilized within shellcraft sectors remains scant. To address this knowledge gap, our study examined diversity, in terms of composition and quantities, of marine taxa utilized by artisan households and, collectively, within an artisanal shellcraft sector of Papua New Guinea. For each taxon, critical source habitats were identified, and the geographic scale of exploitation established. Critically, presented data revealed 73 taxa, representing at least 77 species, were utilized within the studied sector. Many of the taxa utilized had not previously been linked to shellcraft sectors, demonstrating that a broader composition of taxa is utilized than previously acknowledged. In terms of quantity, annual utilization within the sector was close to 500,000 individuals, the majority being mollusks of either class Gastropoda (83.6%), represented by 37 genera, or class Bivalvia (9.6%), represented by four genera. There was a strong bias towards a particular species,
Chrysostoma paradoxum
(78.5% of all individuals), as indicated by indices for the diversity utilized (
H
′ = 1.23;
D
= 0.38). However, substantial variation was evident in the diversity of taxa utilized among households (
n
= 36) engaged in shellcraft (
H
′ = 1.09 ± 0.71;
D
= 0.43 ± 0.27), with each household utilizing a unique composition of 19.1 ± 10.6 taxa. Source habitats for taxa ranged from pelagic to benthic intertidal and subtidal substrates, with the geographic scale of exploitation extending to 34 discrete locations up to 417 km away. The array of sector, household, and taxon-specific information presented provides a basis for supporting greater sustainability within shellcraft sectors across the Indo-Pacific, which is discussed within a context of informing community-based resource management, further developing marine aquaculture, and strengthening existing governance.
Throughout the Pacific Islands, shellcraft has begun to feature prominently in development intervention which aims to generate positive livelihood outcomes for coastal communities. This activity ...often involves the post-harvest processing of natural assets, namely shells and skeletal remains of marine taxa, into jewellery by individuals or small-sized enterprises. To foster participation in shellcraft, development intervention commonly involves gifting or subsidising physical assets. Yet knowledge of the natural (i.e., taxa) and physical (i.e., tools) assets required for shellcraft remains scant. An understanding of human dimensions in shellcraft pertaining to patterns in asset use, such as how tool ownership differentiates taxa utilised and products produced, is important for determining if access to a specific tool is necessary, or an encumbrance, for achieving a desired outcome. In this study, we identified tools used and variation in tool ownership among artisans engaged in shellcraft to afford an accurate and realistic understanding of the tools required to participate in this activity. We then evaluate how ownership of a specific tool or type of tool differentiates both taxa utilisation and product production for shellcraft. Results indicate ownership of neither all nor any specific tool was required to participate in shellcraft, with artisans typically owning a unique combination of tools. Furthermore, results identified that some specific tools were critical for affecting the attractiveness of utilising certain taxa or producing certain products. Implications of the significant relationships between specific tools and certain taxa or products are discussed in the context of development intervention and commonly articulated theories of change where shellcraft is linked to subsistence fishing, aquaculture, or tourism.
Coral reef fishes exhibit extreme diversity in colouration, with many species being recognised as having colour polymorphism. While melanin-based colouration is known to occur in clownfishes ...(Pomacentridae), little is known about the frequency at which melanistic morphs occur in natural populations. The aim of this study was to assess the frequency of melanistic morphs in a coexisting population of nine clownfishes and to identify ecological covariates associated with morph distribution. In the Kavieng lagoonal system of Papua New Guinea (2°36ʹS, 150°46ʹE), melanistic morphs were found in
Amphiprion chrysopterus
(56 % of individuals),
A. clarkii
(29 %),
A. percula
(20 %), and
A. polymnus
(25 %) populations.
A. leucokranos
,
A. melanopus
,
A. perideraion
,
A. sandaracinos
, and
Premnas biaculeatus
populations were also surveyed, but were found to be without melanistic morphs. Unbiased recursive partitioning analyses identified a suite of interacting and conditional ecological factors encompassing social rank, host anemone species, and location effects as the primary factors predicting the distribution of melanistic morphs. Melanistic morphs were generally associated with host anemones from the genus
Stichodactyla
and with fish having a high social rank. The lack of a distinct melanistic morph locational ‘hot spot’ common to all species, despite locational coexistence, suggests that causative factors of location effects were different among species. Our results highlight the complexity of clownfish polymorphism associated with melanism, with multiple non-exclusive potential explanations identified for future investigation.
Lack of coherent information policies (SPC, 1988; Blanchet, 1990) coupled with poor conservation of public records (Bell, 2003; Rose et al., 2009) has generated an abundance of isolated reports which ...are now only available from repositories of formal colonial authorities and international agencies. While artisanal fishing for subsistence has occurred for millennia (Swadling, 1976, 1977; Szabó and Amesbury, 2011), escalation of exploitation for both subsistence and export markets has occurred in the last several decades or centuries (Dalzell et al., 1996; Gillett and Lightfoot, 2001). Since the introduction of colonial capitalist economies to the region (ca. 1800s) (Cariño and Monteforte, 2009), export-driven mother-of-pearl (MoP) fisheries, which target pearl oysters (Pinctada spp.), greensnail (Turbo marmoratus), and trochus (Rochia nilotica) for their nacreous shells, have made and continue to make important contributions to household earnings (Hawes et al., 2011; Purdy et al., 2017; Vieira et al., 2017; Gillett et al., 2020; Purcell et al., 2021). With past exploitation inevitably influencing the status of present-day populations of these commodities (Berzunza-Sanchez et al., 2013), resulting in local depletion in some cases (Chesher, 1980; Kelso, 1996; Kile, 2000; Pakoa et al., 2014), there is scope for historical data to provide valuable insight into the scale, nature, and timing of human influences on MoP fisheries. Methods Data Collection Data were collected from two sources: (1) physical records and (2) the electronic data management system maintained by PNG National Fisheries Authority.
This study investigated the genetic structure, diversity, and migratory patterns of hawksbill turtles (
Eretmochelys imbricata
) from two nesting locations in Papua New Guinea (PNG) using ...mitochondrial DNA (mtDNA) sequencing and satellite telemetry. Tissue samples collected from nesting female hawksbill turtles (n=75) in PNG revealed a total of 6 haplotypes from the Conflict Group site and 5 haplotypes from Kavieng site, with the Conflict Group and Kavieng samples significantly differing from one another and all other known Asia-Pacific stocks. This finding expands our understanding of the genetic stock structure of hawksbill turtles in the Asia-Pacific region, resulting in 9 Management Units (MUs) now published. Satellite tracking of 15 hawksbill turtles revealed that all individuals migrated from the Conflict Group westerly towards foraging areas in eastern Australia (93%) and PNG (7%). With a mean migration path distance of 1241 ± 108 km, three distinct migration strategies were used by the 10 hawksbill turtles that made it to their foraging grounds in the I) eastern Torres Strait, II) Far North Queensland, and III) western PNG waters. A broad scope of home-range strategies and sizes (95% UD) were used, and in comparison to other studies further postulates that hawksbills are connected to non-specific foraging grounds associated with food source availability. This study provides for the first time in PNG essential insights into hawksbill turtle population structure and connectivity in the western Pacific region, highlighting the importance of effectively conserving and managing this critically endangered species as distinct population stocks. Furthermore, we make recommendations for national and regional conservation strategies and transboundary management to ensure the long-term survival and recovery of western Pacific’s hawksbill turtle populations.
As fish stocks become depleted, exploitation eventually fails to be cost-efficient. However, species or morphs of species can suffer from continual exploitation if their rarity results in increased ...value, justifying the cost-efficiency of targeted or opportunistic exploitation. The trade in coral reef fishes for public and private aquaria is an industry in which naturally rare species and rare morphs of species command high prices. Here we investigate the relationship between price and the natural prevalence of colour morphs of two highly demanded clownfish species using a localised case study. The export prices for colour morphs increased with decreasing prevalence of occurrence (y = 4.60x−0.51, R2 = 0.43), but price increase was inversely less than the observed reduction in prevalence. This renders rare colour morphs (i.e., those at relatively low prevalence) at risk of opportunistic exploitation. Using ecological data, we also demonstrate how this increased value can subject rare colour morphs with aggregated distributions to targeted exploitation. These findings are discussed in relation to the broader marine aquarium trade, identifying taxa potentially at risk from exploitation motivated by rarity and addressing potential management strategies.
Despite the Convention on Biological Diversity (CBD) defining 20 targets across 5 strategic goals, Target 11, which relates to protected areas, has received the most emphasis from donors, ...non-government organisations, and governments, as a performance standard for conservation in Melanesia. Protected area targets, however, may not be culturally or technically appropriate for Melanesian countries, such as Papua New Guinea (PNG), where resource extraction is central to development. In PNG, most protected areas are ineffective and generally lack government support. Despite this, donors continue to link conservation funding to protected areas and CBD coverage targets. We argue that pressure to establish protected areas and report against numerous multilateral environmental agreements not only fails to deliver conservation benefits, but also wastes scarce resources and retards the development of sustainable conservation approaches in Melanesia. Rather than aspiring to arbitrary spatial targets as set by the CBD, Melanesian governments need to develop appropriate conservation strategies which have incremental approaches that build capacity, improve data quality, and mainstream biodiversity priorities. Low governance capacity remains a major barrier to Melanesian conservation, so greater funding needs to be directed to administrative effectiveness because without a government-driven conservation agenda, biodiversity protection—and protected areas—will inevitably fail.
In this paper we discuss differences in the ways transnational conservationists and Melanesian farmers, hunters and fishers value ‘biodiversity’. The money for conservation projects in developing ...countries originates from people who are embedded in a capitalist system, which allows engagement with nature as an abstract entity. Their western education has given them a scientific/ evolutionary-based worldview, which attributes intrinsic value to all species (and particular arrangements of species, e.g. rainforests and coral reefs), irrespective of economic value or ecosystem function. Because this value system is mostly not shared by the custodians of the biodiversity that conservationists want to save, alternative tactics and arguments are utilised. These inevitably take the form of so-called ‘win-win’ economic rationales for preserving biodiversity, most of which do not work well (e.g. bioprospecting, ecotourism, non-timber forest products, environmental certification schemes, payments for ecosystem services, etc.), for reasons which we detail. Agriculture- and aquaculture-based livelihoods appear to enjoy more success than the ‘win-win’ options but do not necessarily obviate or deter further biodiversity loss. Artisanal use of species-poor but productive and resilient pelagic fisheries is increasing. These ecological and economic realities bring into sharp focus the importance of understanding differences in value systems for successful biodiversity conservation in the tropics.
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