Sawfish

In 2001, paired-trawl comparisons were made during prawn trawl operations to assess the effect of turtle excluder devices and bycatch reduction devices on a range of species groups caught in tropical Australia. This study is one of the first to evaluate the commercial use of these devices in a tropical fishery. Nets with a combination of a turtle excluder device and bycatch reduction device reduced the catches of turtles by 99%, seasnakes by 5%, sharks by 17.7%, rays by 36.3%, large sponges by 85.3%, and small bycatch by 8%, however, these results were largely attributable to the influence of the turtle excluder devices. Nets with both devices also reduced the catch of commercially important prawns by 6%, but the proportion of soft and damaged prawns was reduced by 41%. The combination of these devices had no measurable impact on catches of any of the three byproduct species groups: Thenus spp. (Moreton Bay bugs), Teuthoidea spp. (squid) and Amusium pleuronectes (scallops). Turtles excluder devices reduced the numbers of larger sharks and rays (>1 m) by 86% and 94%, respectively. They did not reduce the total number of sawfish caught, but did reduce the number of the most commonly caught species -the narrow sawfish (Anoxypristis cuspidata) -by 73.3%. Upward-and downward-excluding turtle excluder devices performed about equally for most species groups, although upward excluders were more effective for sharks and less effective for large sponges. The performance of BRDs was poor for most groups and could be improved by using them in more effective positions such as closer to the codend catch. The use of these devices is a major step towards ensuring the long-term conservation of many species, especially endangered sea turtles and vulnerable elasmobranchs. As fishers become more experienced in their use, we are optimistic that the fishery's impact on bycatch will reduce even further. Crown

Increasing exploitation effort and efficiency have been leading to population declines and extinctions among large marine animals. Understanding the magnitude of such losses is challenging because current baselines about species' abundances and distributions in the sea were mostly established after humans had started affecting marine populations. For artisanal fisheries, from which written historical records are rarely, if ever, available, approaches based on gathering anecdotal information from fishers' knowledge are a promising method to know the past environmental conditions. We interviewed coastal artisanal fishers, with ages varying from 15 to 85 years, to detect temporal changes in the catch abundance of large fish species, particularly the largetooth sawfish Pristis pristis and the goliath grouper Epinephelus itajara within Abrolhos Bank, Brazil. Most fishers considered that fishing has led to species depletion. However, older fishers reported significantly more species and larger species as depleted than young fishers. Older fishers caught significantly larger largetooth sawfish and goliath grouper in the past than younger fishers. The largetooth sawfish has not been caught or sought for more than 10 years. Probabilistic tests provided no definitive evidence for local extinction, although the past record of sightings indicates a population decline close to the threshold level for extinction probability. We provide evidence that small-scale artisanal fisheries can decimate the abundance of large coastal fishes, one of those almost close to local extinction. Finally, our results suggest that the younger generation is not aware of past ecological conditions , indicating the occurrence of a shifting baseline syndrome among the fishing community.

Prior to protection of all species of sawfishes under CITES (September 13, 2007; http://checklist. cites. org/#/en) and the Endangered Species Act (January 12, 2015; NMFS 2014), sawfish rostra were long traded among dealers and collectors of natural history objects. Traffic in these distinctive curios was common for nearly 2 centuries (Norman & Fraser 1938, Migdalski 1960, Hoover 2008). Specimens imported from the Indo-Pacific were commonplace as late as the 1960s in retail shell shops and souvenir stores in coastal towns of the United States. Once dried, sawfish rostra were well suited for long-term storage due in part to being composed primarily of cartilage re inforced with calcium. As a result, despite

Management and recovery of endangered sawfishes are challenged by the uncertainty of species determination. Frequently, dried rostra (saws) are the only material available to represent an historical occurrence, yet traditional methods of species identification of data deficient rostra (rostral tooth counts) are unreliable. We evaluated the utility of morphometric characters for the identification of specimens from 2 private collections totaling 41 rostra and representing 4 species: Anoxypristis cuspidata, Pristis pectinata, P. pristis, and P. zijsron. Rostra were acquired as available and the sample is likely representative of sawfishes globally. Data on 9 morphometric and meristic variables were collected, 5 of which were evaluated using principal component
analysis (PCA). PCA of the mensural data accounted for 87% of the variance with the first 2 principal components. Principal component 1 (PCI) was explained by 4 variables and PCII by a single variable. This indicated that all 5 variables were taxonomically important. Spatial relationships of points were consistent with putative identifications based on available data. Knifetooth sawfish (A. cuspidata), smalltooth sawfishes (P. pectinata and P. zijsron), and largetooth sawfishes
(P. pristis) formed 3 distinct clusters with minimal overlap along PCI. P. pectinata and P. zijsron were separated from each other along PCII, as were the P. microdon (nom. dub.) (Indian and Pacific) and P. perotteti (nom. dub.) (Atlantic) populations of P. pristis. The results demonstrate the utility of analyzing private collections of historically traded rostra. Cumulatively, such collections represent a global fauna sampled over many decades with potential for characterizing phenotypic variation in sawfish at interspecific and intraspecific levels on a greater geographic and temporal scale than targeted modern sampling of specific populations. Further, PCA provides an objective way of classifying data-deficient rostra to species, greatly increasing the research value of these
specimens.