Ultrasonic transmitters were surgically implanted into adult tautog (n=27, 400-514 mm TL) to document seasonal occurrence and site utilization at four sites situated within known tautog habitat near ...Cape Charles, Virginia, in lower Chesapeake Bay. Tagged tautog were released at the same sites where originally caught within 2 h of capture. Sites were continuously monitored with automated acoustic receivers between 9 November 1998 and 13 October 1999. Two sites consisted of natural bedform materials and two sites consisted of manmade materials. Ninety-four percent of tautog (n=15) released in fall 1998 remained inshore during winter at sustained water temperatures of 5-8 degree C, rather than moved offshore during winter as documented for tautog off New York, Rhode Island, and Massachusetts. Ninety-one percent (n=10) of tautog released in spring 1999 remained inshore during summer when water temperature was 27 degree C and in the absence of an important food item, blue mussels (Mytilus edulis). These findings conflict with assertions that tautog move to cooler water in summer when water temperatures reach 20 degree C. Tautog released at natural bedform sites were detected only at these sites throughout the study. Tautog released at manmade structures also displayed high site-utilization patterns, but several tautog periodically moved 2-10.2 km away from these sites over featureless bottom, a known deterrent to emigration for large temperate labrids in other waters. Benthic communities were similar at manmade sites and natural bedform sites, and movement away from manmade sites may have been influenced by habitat size as well as habitat structure. Understanding temporal and spatial utilization of habitats is an important first step to identifying essential fish habitat and to evaluating and protecting fishery resources within Chesapeake Bay and elsewhere.
Adult bucephalid trematodes (Digenea) generally only occur in piscivorous fish. Within labrid fishes they are very rare, however, we have found them in labrid cleaner fish that feed on the ...ectoparasites of fish. We surveyed 969 labrid fishes from the tropical Pacific and found bucephalids only in cleaners (Labroides dimidiatus, L. bicolor, and Bodianus axillaris) and none in piscivores. The prevalences of bucephalids in L. dimidiatus at Lizard Island, Heron Island, Orpheus Island (all on the Great Barrier Reef), New Caledonia, and Moorea (French Polynesia) were 51, 47, 67, 56, and 67%, respectively. All of the L. bicolor examined from Moorea were infected. Bucephalids were highly prevalent in all size classes of L. dimidiatus from Lizard Island. Bucephalids were found in a 1.6-cm long juvenile L. dimidiatus, in which, piscivory is highly unlikely. We examined the literature on the worldwide bucephalid fauna in labrids and all hosts were found to be cleaners (Symphodus tinca, S. mediterraneus, L. dimidiatus, L. bicolor, and Bodianus axillaris) except Notolabrus parilus, whose ecology is unknown. We suggest that cleaners eat bucephalid metacercariae directly from the exterior surface of client fish during cleaning interactions. This is the first evidence of digeneans in the diet of L. dimidiatus, and the first study to show this novel form of parasite transmission where infective stages are eaten as a result of cleaning behaviour. Cleaning-mediated parasite transmission may result in behavioural modification of second intermediate hosts because clients and parasites both benefit from transmission. If the infection is costly to cleaners and acquired during cheating behaviour, then this parasite might regulate mutualism. Alternatively, if infective stages are targeted, infection by these bucephalids may be a negative consequence of an honest foraging strategy.PUBLICATION ABSTRACT
The importance of the canopy of small-sized seagrasses (Cymodocea nodosa and Zostera noltii) to fish assemblages was investigated in experimental plots at three shallow sites in NE Sardinia (Italy, ...western Mediterranean). Fish were assessed by underwater visual census in four habitats: (1) seagrass in its natural state, (2) cut seagrass, (3) uncut seagrass (with a simulation in time and effort equivalent to those spent at the treated patches) and (4) unvegetated sand. The disturbance associated with removing seagrass canopies was not found to affect fish. Multivariate analyses showed that fish assemblages from seagrass habitats, with seagrass patches removed and unvegetated sand differed significantly among each other. Univariate analyses revealed that species richness, total fish abundance, and densities of Atherinidae, Diplodus sargus and Sarpa salpa were unaffected by the habitat type. The seagrass leaf canopy was most important for Symphodus ocellatus, Labrus viridis, Diplodus annularis and Sparus aurata, the last three species being chiefly represented by small-sized fishes. Gobiids were most abundant in habitats devoid of seagrass vegetation (i.e. sand and removed patches), while Coris julis and Diplodus vulgaris appeared to prefer unvegetated sand, even compared with the removed patches. Other species, such as Symphodus cinereus, Symphodus tinca and Mullus surmuletus, did not display any distinct distribution patterns attributable to the habitat type. For a number of littoral fish species, including some of commercial importance (e.g. S. aurata), small-sized seagrasses in NE Sardinia were thus demonstrated to exert an ecological role, which involves important implications for the protection and management of these coastal habitats and suggests the need for further research at larger spatial scales.
Trypsin is a highly valuable protease that has many industrial and biomedical applications. The growing demand for non-animal sources of the enzyme and for trypsins with special properties has driven ...the interest to clone and express this protease in microorganisms. Reports about expression of recombinant trypsins show wide differences in the degree of success and are contained mainly in patent applications, which disregard the difficulties associated with the developments. Although the yeast
Pichia pastoris appears to be the microbial host with the greatest potential for the production of trypsin, it has shown problems when expressing cold-adapted fish trypsins (CAFTs). CAFTs are considered of immense value for their comparative advantage over other trypsins in a number of food-processing and biotechnological applications. Thus, to investigate potential obstacles related to the production of CAFTs in
P. pastoris, the cunner fish trypsin (CFT) was cloned in different
Pichia expression vectors. The vectors were constructed targeting both internal and secreted expression and keeping the CFT native signal peptide. Western-blotting analysis confirmed the expression with evident differences for each construct, observing a major effect of the leader peptide sequence on the expression patterns. Immobilized nickel affinity chromatography yielded a partially purified recombinant CFT, which exhibited trypsin-specific activity after activation with bovine enterokinase.
The nesting activity of the littoral five-spotted wrasse, Symphodus roissali, was investigated near Blanes (northwestern Mediterranean Sea). Males construct and defend several nests over the entire ...reproductive period while females spawn asynchronously in these nests. Nesting activity continued from around the end of March to the end of June in the case of the study population. Nesting intensity, nesting success and nest destruction varied between years and sites. Differences between the numbers of nests that survive the nesting cycle and those that are destroyed can be related to environmental conditions, primarily wave height. Sufficiently protracted periods (> 1 week) of favourable sea conditions allow nests to survive and complete their cycle.
A new species of Sanguinicola Plehn, 1905 is described from the marine teleosts Notolabrus parilus (Richardson) and N. tetricus (Richardson) (Perciformes: Labridae) from Western Australian and ...Tasmanian waters. This host distribution is strikingly anomalous; however, the present material fulfils the morphological criteria of Sanguinicola. S. maritimus n. sp. differs from previously described species in having the combination of a body 1,432--1,701 mum long, the oesophagus 18.3--21.7% of the body length, the testis occupying 42.8--52.3% of the body length, an oviducal seminal receptacle and Mehlis' gland present, ovoid eggs, and vitelline follicles that extend anteriorly past the nerve commissure, laterally past the lateral nerve chords and posteriorly to the anterior margin of the cirrus-sac. S. maritimus also lacks a protrusible anterior proboscis. It also differs in the combination of host and geographical location, being the first Sanguinicola species from a marine teleost and the first from Australian waters.
. A study of the structure of the fish community associated with a vermetid reef at Shiqmona, Israel, revealed the highest fish biodiversity (36 species) of any habitat along the Mediterranean coast ...of Israel. Despite the prevalence of fish of Erythrean origin in the Levantine littoral, the benthic fish community at the site is entirely autochthonous. The families richest in members were the Blenniidae and the Gobiidae. Eighteen species are benthic, sixteen supra‐benthic and two pelagic.
The lipid content and fatty acid composition of the small common wrasse Symphodus ocellatus was analysed within two populations located in very different biotopes on the French shore: a Caulerpa ...taxifolia meadow located in Cap Martin and a Posidonia oceanica bed located in Villefranche. Polar lipids represented 82-90% of the total lipid in adult female livers, gonads and in eggs. Cholesterol in gonads and eggs and triacylglycerols in livers were the dominant neutral lipids. Differences in lipid classes were found in livers between the two populations, but not in their gonads and eggs. Moreover, a quantitative difference in total lipid content was evident. Young fish living on the C. taxifolia meadow in winter had 21% less lipid than those living on the P. oceanica bed. The populations of S. ocellatus showed differences between triacylglycerol versus phospholipid fatty acid compositions and between gonad versus liver fatty acid compositions. Moreover, a significant difference was found between both populations in their liver triacylglycerol fatty acid compositions, suggesting a difference in diet. Gut content analysis supported this hypothesis as it showed important differences in the ingested preys between the two populations in January (planktonic vs. benthic, frequency of isopods) and in June (frequency of gastropods). Thus, we found that the fish populations from Villefranche and Cap Martin showed significant differences in body lipids due to different nutritional habits.PUBLICATION ABSTRACT
Physical factors influencing the distribution and abundance of seven common labrid fishes were examined over four rocky reef locations in northeastern New Zealand. Depth and exposure for each species ...(both within and among sexes) were related to pectoral fin aspect ratio. Each of the four locations (two mainland and two island) displayed distinct labrid assemblages, which were consistent over time, likely due to the influence of the East Auckland Current. There was a consistent depth-related trend for most species, regardless of location. Several species also showed a sex related depth difference. There was also a trend for some species to be associated with certain levels of wave exposure. For most species, the relationship between pectoral fin aspect ratio and the above physical variables was not as strongly evident in this temperate assemblage as has been previously found in tropical reef fish systems. Although some species did follow the predicted shifts in fin aspect ratio with depth and/or exposure, the observed trends were unrelated to fin aspect ratio for many other species. These findings suggest that wave exposure may not be as important for labrids on northeastern New Zealand reefs as it may be in tropical coral reefs systems. The lower fin aspect ratios for New Zealand labrids, compared to tropical labrids, suggest that New Zealand labrids represent a subset of the total pectoral fin diversity in the Labridae. Consequently, the potential for distinct trends in fin aspect ratio and physical variables to be evident may be reduced.
We studied territorial behaviour of the acanthurid surgeonfish Acanthurus sohal and pomacentrid damselfish Plectroglyphidodon leucozona on fringing reefs in Ras Mohammed National Park, Red Sea, ...Egypt. We investigated trespass times, the number of agonistic acts, their intensity and the agonism elicited (number agonistic acts/total trespass time) for all intruders. Five families (Pomacentridae, Chaetodontidae, Acanthuridae, Labridae and Scaridae) were dominant among the 14 we recorded in our study sites. Seven species belonging to four families were resident inside A. sohal territories. Of the other 66 species we observed, 45 are intruders. The territory-holder did not react equally agonistically toward all these intruders. A. sohal showed a high number of agonistic acts against conspecifics and the parrotfish Cetoscarus bicolor. The intensity of the agonistic encounters, however, showed a different picture, with a low level for conspecifics and C. bicolor, respectively. A. sohal showed a high degree of agonistic intensity toward only one parrotfish, Chlorurus sordidus. The highest values of 'Agonism elicited' were recorded against Scarus ghobban, followed by Siganus rivulatus and Zebrasoma desjardinii . Despite these high values, the intensity was relatively weak. The territories of A. sohal were large (average 12.5m^sup 2^); those of P.leucozona were ca. 20 times smaller (average 0.6m^sup 2^). A. sohal spent most of their time swimming (patrolling) along the territory border, stopping briefly to feed on algae. On the other hand, P. leucozona spent most of their time swimming and sheltering.PUBLICATION ABSTRACT
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