A review of the Papua New Guinea marine aquarium fishery

The marine aquarium trade is characterised by numerous source countries that collect a diversity of coral reef associated fishes and invertebrates primarily destined for private and public aquaria worldwide. While aquaculture accounts for a few species entering the trade, the bulk of diversity must still be collected from wild populations. With most organisms being sourced from economically marginalised countries in the Indo-Pacific region, the marine aquarium trade has potential to offer a sustainable livelihood opportunity to the custodians of these source habitats. However, in the absence of appropriate management, unsustainable practices can flourish, including use of anaesthetising chemicals (i.e., sodium cyanide) and physical reef damage to collect organisms. In order for long-term benefits of the marine aquarium trade to be accrued by local custodians, effective management systems must be in place. The marine aquarium fishery of Papua New Guinea (PNG) first opened in 2008 and was relatively short lived, closing in 2012. The fishery operated under both a government funded consultancy (2008-2010) and a private commercial entity (2011-2012). Since then, no further commercial exports of marine aquarium organisms have occurred. The apparent lack of viability in this fishery has not yet been evaluated. It is uncertain to what extent government management, operator practices, or consumer attitudes impacted the viability of initial operations. This thesis examines those factors anticipated to impact on the viability of marine aquarium fishery operations within PNG and extends these findings to marine aquarium fisheries at a regional and global level. The existing system of management, encompassing spatial restrictions of fishing effort, limited entry through licensing, gear restrictions, bans on destructive fishing methods, and species-specific Total Allowable Catches (TACs) for 369 species created an unsustainable management burden bourne by the fishery. The collection practices of the PNG fishery were found to be highly selective, collecting fishes disproportionate to their availability (i.e., TAC), rendering many of the established species-specific TACs obsolete. Specifically, 53.2 % (n = 142) of fish species and 87.3 % (n = 89) of invertebrate species with assigned TACs were never collected by the commercial fishery in 2011-2012. A further 124 fish species were collected in the absence of assigned TACs. Of the fish and invertebrate species collected, only three fish species (Amphiprion percula, Paracanthurus hepatus, and Hemiscyllium hallstromi) were found to merit species-specific TACs. By narrowing the focus of species-specific management to those species actually requiring such management attention this refinement of TAC use will reduce the management burden posed by the fishery. The selectivity of the marine aquarium fishery was found to extend beyond species to specific colour morphs of species. This was true for two of the most collected species, A. percula and Premnas biaculeatus. The export price of rare colour morphs was found to increase with decreasing natural abundance (y = 4.73x-0.53, R2 = 0.97), but were well below the value-for-rarity threshold (y = 4.21x-1.00) derived from the price of regular morphs. This suggests the observed targeted exploitation of rare clownfish morphs in the PNG fishery was a less profitable fishing strategy than opportunistic exploitation, where fishes are collected by random encounters. Supply-chain losses attributed to both quality control rejections and mortality were high in 2010. Quality control rejections accounted for a supply-chain loss of 24.2 % of fishes and 11.5 % of non-CITES invertebrates. Among the accepted catch, a mortality of 27.3 % of fishes and 30.6 % of invertebrates occurred prior to export. Where losses occur after purchasing organisms from fishers, this comes as an economic loss to the exporting operator. The loss of one out of every three purchased organisms would have greatly impacted on the economic viability of the fishery. This finding also raises concern over the accuracy of trade data (i.e., export invoices) to accurately monitor exploitation of the trade and raises ethical concerns in regards to humanitarian standards for the treatment of animals. In the absence of prior reviews of practice, the PNG marketing approach of "sustainability" appears to have engendered consumer support for PNG marine aquarium fishery products. In an online survey, consumers were found to show preference for buying a PNG fish over fish sourced from Vietnam, Indonesia, or the Philippines. However, consumers were more likely to purchase fish independently certified for themes of environmentally sustainable, industry best practice, or revenue supporting indigenous fishers compared to purchasing fish from any of the specific countries included in the survey. This suggests consumers want product information validated by a trustworthy third-party. At a global scale, there is minimal evidence that media influences consumer demand, with consumer demand appearing to be more dependent on global economy and advancements in captive husbandry technology. The viability of the marine aquarium trade in PNG appears to have been largely hindered by supply chain losses. While this was empirically evaluated in 2010, there appears to have been little improvement within the fishery as export invoices underestimated catch by 29.3 % in 2012. As such, a direct comparison of the PNG fishery is made to a long-running Fijian supply chain. This identifies areas requiring improvement for better viability of future marine aquarium trade operations in PNG. The research contained within this Thesis is likely to be of interest to PNG, regional marine aquarium fisheries, and the global marine aquarium community

Influence of Moult Cycles on Digestive Enzyme Activities during Early Larval Stages of Panulirus ornatus

The tropical spiny lobster, Panulirus ornatus, has a complex life cycle characterised by a series of moults that occur throughout pelagic larval stages. Significant morphological, physiological, and biochemical changes commonly coincide with moulting and can have dietary implications when culturing this species. Digestive enzyme activities respond to nutritional requirements and have provided useful insight into nutrient use dynamics associated with first-feeding in P. ornatus. Beyond first-feeding, however, information on digestive enzyme activities in P. ornatus is scarce. Greater knowledge of fluctuations in digestive enzyme activities during moult cycles should facilitate better formulation of feeds and more efficient feeding regimens. As an initial step towards this goal, the present study evaluated the influence of moult cycles on digestive enzyme activities during early larval stages of P. ornatus. The investigation focused exclusively on early larval stages (stages I-III) when delivery of appropriate feeds and nutrition can dramatically affect subsequent growth and survival

Anaesthetic induced relaxation of the winged pearl oyster, Pteria penguin, varies with oyster size and anaesthetic concentration

Stress and mortality of pearl oysters during nucleus implanting for round pearl and mabé pearl production can be reduced using appropriate anaesthetics that allow improved access to nucleus implanting sites. This study evaluated the efficacy of three different concentrations of benzocaine (0.25, 0.50 and 1.20 g L-1) and 1-propylene phenoxetol (2.50, 3.00 and 3.50 mL L-1) when presented to ‘small’ (dorso-ventral height [DVH], 78.7 ± 1.6 mm), ‘medium’ (DVH, 118.2 ± 2.0 mm) and ‘large’ (DVH, 149.3 ± 1.1 mm) cohorts of the winged pearl oyster, Pteria penguin. Results showed the following general trends across treatments with both anaesthetics: (1) greater proportions of large oysters became relaxed compared to small oysters; (2) large oysters required shorter exposure times to become relaxed than small oysters; (3) for each size class of oyster, an increase in anaesthetic concentration resulted in an increased proportion of relaxed oysters; and (4) ‘mantle collapse’ (where the mantle collapses away from the shell) was only recorded in large oysters in treatments with higher concentrations of anaesthetics. The most effective concentration of benzocaine to use with small, medium and large Pt. penguin was the highest level tested in this study (1.20 g L-1). Similarly, the highest concentration of 1-propylene phenoxetol tested (3.5 mL L-1) was also the most effective with all three size classes of Pt. penguin. These treatments caused mantle collapse in large oysters, for which use of lower, less effective anaesthetic concentrations may be considered preferable, to avoid potentially negative impacts of mantle collapse on subsequent mabé pearl production. As well as efficacy, choice of anaesthetic should consider ease of preparation and preparation time. Benzocaine requires dissolving in methyl alcohol and heating to 88–92˚C, while 1-propylene phenoxetol is readily soluble in seawater

Natural rarity places clownfish colour morphs at risk of targeted and opportunistic exploitation in a marine aquarium fishery

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

A multivariate approach to morphological study of shell form in cowries (Gastropoda, Cypraeidae): a case study with Umbilia armeniaca (Verco, 1912)

Multivariate approaches to morphological study of shell form have rarely been applied to cowries (Gastropoda: Cypraeidae) with preference, instead, for comparing formulaic notations of shell form that report averages (i.e., means) for key morphometrics such as shell dimensions, their ratios, and counts of apertural teeth. Although widely applied, the “shell formula” does not account for variation among individuals or support statistical comparison between taxa. This study applied a multivariate approach to analyse shell form within the four accepted subspecies of the cowrie, Umbilia armeniaca (Verco, 1912) and included a previously unstudied, and most northerly, population of U. armeniaca from Lancelin, Western Australia. Multivariate analyses readily separated the recognised subspecies of U. armeniaca (U. a. armeniaca, U. a. diprotodon, U. a. clarksoni and U. a. andreyi), but did not separate the Lancelin population from U. a. andreyi, indicating that the former represents a northward extension of U. a. andreyi that is not morphometrically distinguishable. These results provide improved understanding of infraspecific differences in shell form of U. armeniaca across its broad distribution, and demonstrate the utility of multivariate morphometric methods for statistical comparison of shell form between taxa. This approach is complimentary to existing research practices and has broad potential application in future morphometric studies of both extant and fossil taxa within the family Cypraeidae

A new species of Umbilia Jousseaume, 1884 (Mollusca, Cypraeidae) from the Pliocene fauna of the Roe Plains, Western Australia

A new morphologically distinct species of cowry (family Cypraeidae Rafinesque, 1815) is described from the Late Pliocene Roe Calcarenite of the Roe Plains, Western Australia. Previously assigned to Umbilia hesitata (Iredale, 1916), the new species differs morphometrically from related taxa and is differentiated from U. hesitata by a number of shell features including a prominent, projecting protoconch, less extended posterior and anterior terminals, coarser columellar teeth extending onto the base, and well-developed, thickened anterior flanges, supporting a rounded anterior extremity with blunt anterior tips. Umbilia tomdarraghi sp. nov. is the third Umbilia species to be described from the Pliocene

A multivariate approach to morphological study of shell form in cowries (Gastropoda, Cypraeidae): a case study with Umbilia armeniaca (Verco, 1912)

Multivariate approaches to morphological study of shell form have rarely been applied to cowries (Gastropoda: Cypraeidae) with preference, instead, for comparing formulaic notations of shell form that report averages (i.e., means) for key morphometrics such as shell dimensions, their ratios, and counts of apertural teeth. Although widely applied, the “shell formula” does not account for variation among individuals or support statistical comparison between taxa. This study applied a multivariate approach to analyse shell form within the four accepted subspecies of the cowrie, Umbilia armeniaca (Verco, 1912) and included a previously unstudied, and most northerly, population of U. armeniaca from Lancelin, Western Australia. Multivariate analyses readily separated the recognised subspecies of U. armeniaca (U. a. armeniaca, U. a. diprotodon, U. a. clarksoni and U. a. andreyi), but did not separate the Lancelin population from U. a. andreyi, indicating that the former represents a northward extension of U. a. andreyi that is not morphometrically distinguishable. These results provide improved understanding of infraspecific differences in shell form of U. armeniaca across its broad distribution, and demonstrate the utility of multivariate morphometric methods for statistical comparison of shell form between taxa. This approach is complimentary to existing research practices and has broad potential application in future morphometric studies of both extant and fossil taxa within the family Cypraeidae

Beyond symbiosis: cleaner shrimp clean up in culture

Cleaner organisms exhibit a remarkable natural behaviour where they consume ectoparasites attached to "client" organisms. While this behaviour can be utilized as a natural method of parasitic disease control (or biocontrol), it is not known whether cleaner organisms can also limit reinfection from parasite eggs and larvae within the environment. Here we show that cleaner shrimp, Lysmata amboinensis, consume eggs and larvae of a harmful monogenean parasite, Neobenedenia sp., in aquaculture. Shrimp consumed parasite eggs under diurnal (63%) and nocturnal (14%) conditions as well as infectious larvae (oncomiracidia) diurnally (26%). Furthermore, we trialled the inclusion of cleaner shrimp for preventative parasite management of ornamental fish, Pseudanthias squamipinnis, and found shrimp reduced oncomiracidia infection success of host fish by half compared to controls (held without shrimp). Fish held without cleaner shrimp exhibited pigmentation changes as a result of infection, possibly indicative of a stress response. These results provide the first empirical evidence that cleaner organisms reduce parasite loads in the environment through non-symbiotic cleaning activities. Our research findings have relevance to aquaculture and the marine ornamental trade, where cleaner shrimp could be applied for prophylaxis and control of ectoparasite infections

Improved ocean-based nursery culture of blacklip pearl oyster (Pinctada margaritifera) juveniles in mesh baskets using cyanoacrylate adhesive

The blacklip pearl oyster, Pinctada margaritifera, supports well-established cultured pearl industries throughout the Pacific with various nursery culture methods used to on-grow juvenile oysters to a size suitable for pearl production. Locally-available plastic baskets are commonly used to rear juvenile oysters, but they do not prevent oysters from aggregating, which negatively impacts production. To develop an understanding of how basket-based nursery culture might best be adapted for rearing juvenile P. margaritifera, this study examined growth and survival of juveniles of varying sizes and stocked at varying densities in mesh baskets when using a cyanoacrylate adhesive to prevent aggregation. During a 3.5-month ocean-based nursery culture period, stocking density was shown to have a significant effect on growth (F = 11.53, p < 0.001), yet a minimal influence on oyster survival (χ2 = 5.05, p = 0.28). By contrast, stocking size influenced survival (χ2 = 7.17, p = 0.03), but had minimal impact on growth (F = 3.24, p = 0.08). Given that mean ( ± SD) survival of juveniles ranged from 65.0 ± 14.4% to 94.0 ± 8.2% and dorsoventral shell growth ranged from 13.9 ± 6.2 mm to 19.7 ± 6.3 mm, depending on stocking density and stocking size, these factors clearly merit consideration before fixing juvenile oysters to baskets with an adhesive. Such results broaden our knowledge of nursery culture methods for P. margaritifera and improve options for small-scale pearl farmers in the Pacific

Taxonomically constrained reporting framework limits biodiversity data for aquarium fish imports to Australia

Context: Biological resource use represents the most common direct threat to biodiversity. Despite this, there is a paucity of comprehensive and overarching data relating to the biological resource use. The global aquarium trade encompasses millions of individual live fishes representing thousands of marine and freshwater species traded on an annual basis. The lack of specific data systems for recording information where fish are exported or imported has resulted in limited accessible trade data. An evaluation of the data-reporting frameworks presently employed by countries engaged in the aquarium trade is warranted to better understand the means by which comprehensive data on the aquarium trade can be made more accessible. Aims: This study examines the data-reporting framework of The Australian Government Department of Agriculture and Water Resources (DAWR) used to collate aquarium fish import data, and its capacity to inform on the aquarium trade biodiversity imported to Australia. Methods: Aquarium import records from 2010-16 were provided by DAWR and used to determine the quantity of individual fishes and consignments imported to Australia. The potential biodiversity of imports was determined from the Australian Government's List of Permitted Live Freshwater/Marine Fish Suitable for Import 2018 (Number 69, F2017C00079), the legislative document identifying species permitted import to Australia for the aquarium trade. Species permitted import were cross-referenced with the International Union for Conservation of Nature (IUCN) Red List to address whether the Australian aquarium trade is importing threatened species. Key results: A total of 10 320 consignments encompassing more than 78.6 million aquarium fishes were imported to Australia between 2010 and 2016. A total of 4628 species of fishes were permitted import to Australia for the aquarium trade with 73 of the marine species (2.0%) and 81 of the freshwater species (7.5%) found to be threatened with some degree of extinction risk. The data-reporting framework for aquarium fish imports offered limited capacity to taxonomically differentiate imports and only 12.5% of all aquarium fishes imported could be identified to species. Conclusions: The aquarium fish import records provided by DAWR had limited taxonomic resolution and, consequently, limited capacity to contribute to an improved understanding of the biodiversity imported to Australia for the aquarium fish trade. While more detailed information is available than is presently collated by DAWR, the availability of this information is constrained by the laws around protected information and the resources available to DAWR. Implications: Accessible, detailed information on aquarium fish imports is necessary to support comprehensive research capable of addressing threats to biodiversity loss from the aquarium trade. To this end, the means by which Australian aquarium import data can be reported at greater taxonomic resolution under the existing legislative and resource restraints should be explored further