Wrasse Species Research Articles

Fluorescence characterisation and visual ecology of pseudocheilinid wrasses.

BackgroundWrasses represent the second largest family of marine fishes and display a high diversity of complex colours linked to ecological functions. Recently, red autofluorescent body colouration has been reported in some of these fishes. However, little is known about the distribution of such fluorescent body patterns in wrasses or the animals’ ability to perceive such colours.ResultsAgainst this background, we (1) investigated long-wavelength emission autofluorescence in thirteen species of pseudocheilinid wrasses and (2) characterised the spectral absorbance of visual pigments in one of the examined species, the fairy wrasse Cirrhilabrus solorensis. Spectrophotometric analysis revealed that fluorescent body colouration is widespread and diverse within this clade, with considerable variation in both fluorescent pattern and maximum emission wavelength between species. Characterisation of visual pigments in retinal photoreceptors showed a single class of rod and three spectrally distinct cone photoreceptors, suggesting possible trichromacy.ConclusionCombining the emission characteristics of fluorescence body colouration and the spectral sensitivity data of retinal cells suggests that the visual system of C. solorensis is sensitive to pseudocheilinid fluorescence.Electronic supplementary materialThe online version of this article (doi:10.1186/s12983-016-0145-1) contains supplementary material, which is available to authorized users.

Interspecific variation in the spawning time of labrid fish on a fringing reef at Iriomote Island, Okinawa

The diel timing of pelagic spawning in reef fish has been discussed in the context of adaptation to local environmental conditions. However, interspecific variations in spawning time are also known to occur at a single locality. The family Labridae, composed of wrasses and parrotfishes, is one of the largest groups of fish on coral reefs. We investigated the spawning behavior and interspecific interactions of 30 species of wrasse at the same spawning site, a reef edge off Iriomote Island, Okinawa, Japan, where we previously studied 13 species of parrotfish. Six patterns in spawning time, related to time of day and high tide, were distinguished at the spawning site. Most wrasses spawned around high tide in the daytime and a few spawned at dusk only, whereas most parrotfishes spawned in the early morning, and some species exhibited intermediate (mixed) patterns. The interspecific variation in spawning time can be explained at least in part by phylogenetic constraints. Physiological constraints on spawning time are also discussed in relation to the different external cues that activate oocyte maturation.

Anaesthetic protocols for lumpfish (Cyclopterus lumpus L.)

Lumpfish and different species of wrasse have shown to efficiently eat sea lice. Due to the high demand for cleaner fish, lumpfish is now farmed in Europe. In Norway, there has been a rapid increase in production sites the last three years and the number of produced lumpfish has increased from 0.4 million in 2012 to 10 million (estimate) in 2015. There are several situations during the production cycle in which anaesthesia is required or preferred, such as egg stripping, blood sampling and vaccination. At present, some companies use anaesthetic during vaccination of lumpfish, although no systematic testing of effect and safety has been performed. It has to be valuated if anestethetic is beneficial or needed for vaccination of lumpfish. We have developed anaesthetic protocols for three drugs and determined the optimal dose and therapeutic window for each of them. We have also examined the effect of fish size and temperature. This will ensure optimal and safe treatment according to an ethical standard for good fish welfare.

Phylogeography of Indo‐Pacific reef fishes: sister wrasses Coris gaimard and C. cuvieri in the Red Sea, Indian Ocean and Pacific Ocean

AbstractAimThe aim of this study was to resolve the evolutionary history, biogeographical barriers and population histories for sister species of wrasses, the African Coris (Coris cuvieri) in the Indian Ocean and Red Sea, and the Yellowtail Coris (Coris gaimard) in the Pacific Ocean. Glacial sea level fluctuations during the Pleistocene have shaped the evolutionary trajectories of Indo‐Pacific marine fauna, primarily by creating barriers between the Red Sea, Indian Ocean and Pacific Ocean. Here, we evaluate the influence of these episodic glacial barriers on sister species C. cuvieri and C. gaimard.LocationRed Sea, Indian Ocean, Pacific Ocean.MethodsSequences from mitochondrial DNA cytochrome oxidase c subunit I (COI), and nuclear introns gonadotropin‐releasing hormone (GnRH) and ribosomal S7 protein were analysed in 426 individuals from across the range of both species. Median‐joining networks, analysis of molecular variance and Bayesian estimates of the time since most recent common ancestor were used to resolve recent population history and connectivity.ResultsCytochrome oxidase c subunit I haplotypes showed a divergence of 0.97% between species, and nuclear alleles were shared between species. No population structure was detected between the Indian Ocean and Red Sea. The strongest signal of population structure was in C. gaimard between the Hawaiian biogeographical province and other Pacific locations (COI ϕST = 0.040–0.173, P < 0.006; S7 ϕST = 0.046, P < 0.001; GnRH ϕST = 0.022, P < 0.005). Time to most recent common ancestor is c. 2.12 Ma for C. cuvieri and 1.76 Ma for C. gaimard.Main conclusionsWe demonstrate an Indian‐Pacific divergence of < 2 Myr and high contemporary gene flow between the Red Sea and Indian Ocean, mediated in part by the long pelagic larval stage. The discovery of hybrids at Christmas Island indicates that Indian and Pacific lineages have come into secondary contact after allopatric isolation. Subspecies status may be appropriate for these two wrasses.

Phylogenetic analysis and serotyping of Vibrio splendidus-related bacteria isolated from salmon farm cleaner fish.

Cleaner fish, i.e. various wrasse (Labridae) species and lumpsucker Cyclopterus lumpus, are to an increasing extent used for biocontrol of the salmon louse Lepeophtheirus salmonis in European salmon farming. Although efficient de-licers, cleaner fish mortality levels in salmon farms are often high. Bacterial infections are common, and Vibrio splendidus-related strains are frequently identified during diagnostic investigations. The population structure of 112 V. splendidus-related isolates, derived primarily from wrasse species, was investigated by means of multilocus sequence analysis using 5 housekeeping genes (rpoD, ftsZ, pyrH, rpoA and atpA). Most isolates were found to be closely related to the V. splendidus type strain, yet displayed extensive genetic microdiversity. Slide agglutination testing using polyclonal rabbit antisera further indicated O-antigen variability. Intra-outbreak genetic and antigenic diversity suggests direct infection from seawater, rather than fish-to-fish transmission, as the main route of infection. The variable nature of isolates involved complicates qualified selection of representative candidate strains, e.g. for infection and vaccine trials.

Linking cranial morphology to prey capture kinematics in three cleaner wrasses: Labroides dimidiatus, Larabicus quadrilineatus, and Thalassoma lutescens.

Cleaner fishes are well known for removing and consuming ectoparasites off other taxa. Observers have noted that cleaners continuously "pick" ectoparasites from the bodies of their respective client organisms, but little is known about the kinematics of cleaning. While a recent study described the jaw morphology of cleaners as having small jaw-closing muscles and weak bite forces, it is unknown how these traits translate into jaw movements during feeding to capture and remove ectoparasites embedded in their clients. Here, we describe cranial morphology and kinematic patterns of feeding for three species of cleaner wrasses. Through high-speed videography of cleaner fishes feeding in two experimental treatments, we document prey capture kinematic profiles for Labroides dimidiatus, Larabicus quadrilineatus, and Thalassoma lutescens. Our results indicate that cleaning in labrids may be associated with the ability to perform low-displacement, fast jaw movements that allow for rapid and multiple gape cycles on individually targeted items. Finally, while the feeding kinematics of cleaners show notable similarities to those of "picker" cyprinodontiforms, we find key differences in the timing of events. In fact, cleaners generally seem to be able to capture prey twice as fast as cyprinodontiforms. We thus suggest that the kinematic patterns exhibited by cleaners are indicative of picking behavior, but that "pickers" may be more kinematically diverse than previously thought.

Relative Brain and Brain Part Sizes Provide Only Limited Evidence that Machiavellian Behaviour in Cleaner Wrasse Is Cognitively Demanding.

It is currently widely accepted that the complexity of a species’ social life is a major determinant of its brain complexity, as predicted by the social brain hypothesis. However, it remains a challenge to explain what social complexity exactly is and what the best corresponding measures of brain anatomy are. Absolute and relative size of the brain and of the neocortex have often been used as a proxy to predict cognitive performance. Here, we apply the logic of the social brain hypothesis to marine cleaning mutualism involving the genus Labroides. These wrasses remove ectoparasites from ‘client’ reef fish. Conflict occurs as wrasse prefer client mucus over ectoparasites, where mucus feeding constitutes cheating. As a result of this conflict, cleaner wrasse show remarkable Machiavellian-like behaviour. Using own data as well as available data from the literature, we investigated whether the general brain anatomy of Labroides provides any indication that their Machiavellian behaviour is associated with a more complex brain. Neither data set provided evidence for an increased encephalisation index compared to other wrasse species. Published data on relative sizes of brain parts in 25 species of the order Perciformes suggests that only the diencephalon is relatively enlarged in Labroides dimidiatus. This part contains various nuclei of the social decision making network. In conclusion, gross brain anatomy yields little evidence for the hypothesis that strategic behaviour in cleaning selects for larger brains, while future research should focus on more detailed aspects like the sizes of specific nuclei as well as their cryoarchitectonic structure and connectivity.

A small no-take marine sanctuary provides consistent protection for small-bodied by-catch species, but not for large-bodied, high-risk species

Despite calls for networks of no-take sanctuary zones of ‘moderate size’ (10–100km2) to meet both conservation and resource management objectives, there have been a plethora of small (1–5km2) and very small (<1km2) no-take areas created in the last decade globally. For example, the temperate eastern Indian Ocean has a range of small to very small no-take marine areas. The current study focused on the Rottnest Island Marine Reserve off the coast of Western Australia, containing the oldest and largest no-take sanctuary zone in the region (1.6km2, established in 1988) and three newly created no-take sanctuary zones (0.8–0.9km2, established in 2007). Three years of transect and baited video monitoring data (2009–2011) from the four no-take areas were compared inside and outside of the sanctuary zones and to previously published studies of the oldest sanctuary zone. Throughout the three-year study, greater size-structure and biomass of two small-bodied by-catch wrasse species were observed in the oldest sanctuary zone, consistent with previously published studies. In contrast to previously published studies from Rottnest, no consistent differences were observed in any large bodied fished species within the oldest sanctuary zone and no increases in biomass were observed in the newly created no-take areas. The results suggest that small sanctuary zones do not provide consistent protection for larger-bodied fished species, but can for smaller-bodied by-catch species. The generality of these results is limited by the lack of replication due to only one established no-take area in the region, and the large proportion of sand habitats which limited the number of sampling sites for reef fishes within the sanctuaries. However, the results suggest that if consistent protection of large-bodied fisheries species is an objective of no-take areas, representative and replicated sanctuary zones should be of greater size and encompass a greater range of depths and habitats. Such systems will also provide the necessary spatial replication between and within no-take areas to design robust monitoring programs to inform conservation management.

Habitat associations and behavioural patterns of Symphodus spp. (Pisces: Labridae)

The complexity and diversity of physical and biotic habitats are important features influencing the composition of shallow water reef fish assemblages, especially in temperate regions where abundant and diverse algal cover may have an important habitat-forming role. Coastal fish have adapted to these diverse habitats and to the temporal and spatial variations of algal assemblages in different ways. Wrasses are an important group of coastal rocky reef fish which present particular associations to algae in temperate systems. In this study, habitat associations were analysed in three species of wrasses: Symphodus bailloni, Symphodus melops and Symphodus roissali, and their behaviour was recorded. Eight main behavioural categories (comprising a total of 42 different behaviours) were identified: exploring, foraging, resting, agonistic interactions, cleaning, courtship, reproduction and nesting. S. melops occurred on shallower depths and was frequently involved in both intra- and interspecific agonistic interactions with the other wrasse species, although rarely with S. bailloni. S. roissali was associated with microhabitats of smaller size where it frequently hides. Feeding occurred mostly on bedrock habitat when compared to other microhabitats. Foraging and resting showed a marked seasonality in the three wrasses, related to shifts in biotic habitat structure and to changes in the behavioural repertoire during the breeding season.

Sex biased fishing mortality and movement patterns of the dimorphic corkwing wrasse (Symphodus melops)

Sex biased fishing mortality and movement patterns of the dimorphic corkwing wrasse (Symphodus melops)

Variation in the Mating Systems of Wrasses (Labridae) at a Spawning Aggregation Site on Guam, Mariana Islands

Event Abstract Back to Event Variation in the Mating Systems of Wrasses (Labridae) at a Spawning Aggregation Site on Guam, Mariana Islands Terry J. Donaldson1* 1 University of Guam Marine Laboratory, United States The wrasses (family Labridae) exhibit a diverse number of mating strategies and behaviors. This diversity is expressed not only interspecifically but also intraspecifically. At Guam, Mariana Islands, over twenty species of wrasses spawn on a small, shallow coral reef known as Finger Reef that projects outward from the main reef into Apra Harbor. Preliminary observations indicated that the mating system utilized by some wrasses varied within species. To examine why this occurs, I utilized direct visual observations supplemented by underwater video and photography. I recorded the identity of the species courting, the number of individuals participating, the distribution of male mating territories, courtship and spawning behaviors, and courtship success. Field work utilized snorkeling for several hours a day variously within the lunar month during 2013-2015. I found that courtship and spawning occurs either in temporary resident spawning aggregations or within a protogynous haremic mating system. Within spawning aggregations, mating systems include a lek-like system with paired spawning, and group or promiscuous spawning. Haremic species followed the traditional single male-multiple female model. Both group-spawning and haremic species, however, also spawned in simple male-female pairs. Sneaking or streaking behavior during pelagic spawning events were observed in all mating systems. The results of these observations found that lek-like behavior and group spawning were dependent upon higher densities of males and females at the site. At lower densities, however, some species reverted to simple paired spawning while others used a haremic system rather than a lek-like system. This suggests that some species of wrasses practice a mixed strategy that is dependent upon fish density during the courtship period. Keywords: courtship behavior, Egg predation, fish reproduction, Mating systems, Spawning aggregation Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Oral Presentation Topic: Physiology, Behavior and Toxicology Citation: Donaldson TJ (2015). Variation in the Mating Systems of Wrasses (Labridae) at a Spawning Aggregation Site on Guam, Mariana Islands. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00054 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Nov 2015; Published Online: 10 Nov 2015. * Correspondence: Dr. Terry J Donaldson, University of Guam Marine Laboratory, Mangilao, Guam, 96923, United States, terryjdonaldson@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract Supplemental Data The Authors in Frontiers Terry J Donaldson Google Terry J Donaldson Google Scholar Terry J Donaldson PubMed Terry J Donaldson Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Metabolic depression in cunner (Tautogolabrus adspersus) is influenced by ontogeny, and enhances thermal tolerance.

To examine the effect of ontogeny on metabolic depression in the cunner (Tautogolabrus adspersus), and to understand how ontogeny and the ability to metabolically depress influence this species' upper thermal tolerance: 1) the metabolic rate of 9°C-acclimated cunner of three size classes [0.2–0.5 g, young of the year (YOY); 3–6 g, small; and 80–120 g, large (adult)] was measured during a 2°C per day decrease in temperature; and 2) the metabolic response of the same three size classes of cunner to an acute thermal challenge [2°C h−1 from 10°C until Critical Thermal Maximum, CTMax] was examined, and compared to that of the Atlantic cod (Gadus morhua). The onset-temperature for metabolic depression in cunner increased with body size, i.e. from 5°C in YOY cunner to 7°C in adults. In contrast, the extent of metabolic depression was ∼80% (Q10 = ∼15) for YOY fish, ∼65% (Q10 = ∼8) for small fish and ∼55% (Q10 = ∼5) for adults, and this resulted in the metabolic scaling exponent (b) gradually increasing from 0.84 to 0.92 between 9°C to 1°C. All size classes of cunner had significantly (approximately 60%) lower routine metabolic rates at 10°C than Atlantic cod. However, there was no species' difference in the temperature-induced maximum metabolic rate, and this resulted in factorial metabolic scope values that were more than two-fold greater for cunner, and CTMax values that were 6–9°C higher (∼21 vs. 28°C). These results: 1) show that ontogeny influences the temperature of initiation and the extent of metabolic depression in cunner, but not O2 consumption when in a hypometabolic state; and 2) suggest that the evolution of cold-induced metabolic depression in this northern wrasse species has not resulted in a trade-off with upper thermal tolerance, but instead, an enhancement of this species' metabolic plasticity.

A new intracellular bacterium, Candidatus Similichlamydia labri sp. nov. (Chlamydiaceae) producing epitheliocysts in ballan wrasse, Labrus bergylta (Pisces, Labridae).

Certain wrasse species (Labridae) are used as cleaner fish in salmon farms on the Norwegian coast, reducing salmon louse intensities. The pathogen repertoire of wrasse in Norway is poorly known, and the objective of the present study is to describe a novel intracellular bacterium detected in Norwegian Labrus bergylta. Histological examination of gill tissues from ballan wrasse, L. bergylta, revealed epitheliocysts occurring basally to the secondary lamellae in the interlamellar epithelium. Ultrastructurally, these had bacteria-filled inclusions with thickened membranes and radiating ray-like structures (actinae). 16S rRNA gene sequences from the gill bacteria showed the highest (97.1 %) similarity to Candidatus Similichlamydia latridicola from the gills of the latrid marine fish Latris lineata in Australia and 94.9 % similarity to Candidatus Actinochlamydia clariae, causing epitheliocystis in the freshwater catfish Clarias gariepinus in Uganda. A total of 47 gill samples from L. bergylta from Western Norway were screened by real time RT-PCR with an assay targeting Candidatus Actinochlamydiaceae 16S rRNA. Prevalence was 100 %. We propose the name Candidatus Similichlamydia labri sp. nov. for this new agent producing gill epitheliocysts in L. bergylta.

Distribution and habitat preferences of five species of wrasse (Family Labridae) in a Norwegian fjord

AbstractWrasse (Labridae) are used widely as cleaner fish to control sea lice infestation in commercial farming of Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) in Norway. As a result, there is an intense fishery for wrasse along the Norwegian coast. Little is known of the population ecology of wrasse and, therefore, an evaluation of their distribution, demographics, and habitat preferences was required as a baseline from which to assess the impact of the fishery. We analysed experimental catch data from a 3-year survey carried out in 1997–1999 (before the fishery began) during and after the wrasse spawning season in a Norwegian fjord. Corkwing wrasse (Symphodus melops) was always the most abundant species, ranging from 52 to 68% of the catches. Goldsinny (Ctenolabrus rupestris) and rock cook (Centrolabrus exoletus) were the second most abundant species (up to 30%). Ballan (Labrus bergylta) and cuckoo (Labrus mixtus) wrasse represented &amp;lt;2% of the catches. Rock cook was relatively more abundant at more exposed stations, while corkwing wrasse was characteristic of more sheltered stations. Goldsinny and ballan wrasse both occupied mainly intermediate stations in the more protected areas. Smaller fish were found at the most protected areas, while larger fish were found at the more exposed stations. Sex ratio in goldsinny and rock cook varied significantly from year to year. In corkwing, the sex ratio remained the same each year, and females were always in larger proportion (61–66%). Spawning occurred mainly in June for goldsinny, rock cook, and corkwing wrasse. The fact that species composition and/or size distributions vary considerably over very small distances must be considered in monitoring programmes. Erroneous conclusions about shifts in species composition can easily be made simply because sampling gear are set in slightly different areas.

Macropharyngodon pakoko, a new species of wrasse (Teleostei: Labridae) endemic to the Marquesas Islands, French Polynesia.

A new species of wrasse, Macropharyngodon pakoko, is described from the Marquesas Islands, bringing the total number of species of the genus Macropharyngodon to 12. Macropharyngodon pakoko was found at depths from 0-42 m and is endemic to the Marquesas Islands. Macropharyngodon pakoko is similar to M. meleagris, which is widely distributed from the central and western Pacific to Cocos-Keeling in the Indian Ocean, but differs genetically and in several coloration characters: males with irregularly curved black humeral blotch with incomplete iridescent blue border; inverted irregular "U"- shaped band on the cheek; a small black spot at the upper base of the pectoral fin; and background color of the body greenish with faint bluish black spots on each scale. Females lack black pigment on the chest posterior to the ventral attachment of the gill membranes; reddish black blotches on the body are widely spaced, particularly on the head where they are more reddish and half the size of those on body; caudal fin with small, bright yellow spots arranged in narrow vertical bands with pale interspaces; pelvic fins pale with three reddish yellow cross-bands; a small black spot at the upper base of the pectoral fin; and small reddish spots along the base of the anal fin. Juveniles have irregular black blotches on the body, a small black spot instead of an ocellus posteriorly on the dorsal fin and lack large black spots and ocellus on the anal fin.

A survey of wild marine fish identifies a potential origin of an outbreak of viral haemorrhagic septicaemia in wrasse, Labridae, used as cleaner fish on marine Atlantic salmon, Salmo salar L., farms.

Viral haemorrhagic septicaemia virus (VHSV) was isolated from five species of wrasse (Labridae) used as biological controls for parasitic sea lice predominantly, Lepeophtheirus salmonis (Krøyer, 1837), on marine Atlantic salmon, Salmo salar L., farms in Shetland. As part of the epidemiological investigation, 1400 wild marine fish were caught and screened in pools of 10 for VHSV using virus isolation. Eleven pools (8%) were confirmed VHSV positive from: grey gurnard, Eutrigla gurnardus L.; Atlantic herring, Clupea harengus L.; Norway pout, Trisopterus esmarkii (Nilsson); plaice, Pleuronectes platessa L.; sprat, Sprattus sprattus L. and whiting, Merlangius merlangus L. The isolation of VHSV from grey gurnard is the first documented report in this species. Nucleic acid sequencing of the partial nucleocapsid (N) and glycoprotein (G) genes was carried out for viral characterization. Sequence analysis confirmed that all wild isolates were genotype III the same as the wrasse and there was a close genetic similarity between the isolates from wild fish and wrasse on the farms. Infection from these local wild marine fish is the most likely source of VHSV isolated from wrasse on the fish farms.

The Physical Condition and Welfare of Five Species of Wild‐caught Wrasse Stocked under Aquaculture Conditions and when Stocked in Atlantic Salmon, Salmo salar, Production Cages

AbstractSeveral indices were examined to assess the physical condition of wrasse stocked on Atlantic salmon, Salmo salar, farms as cleaner fish, and included examination of eye condition, snout erosion, skin hemorrhaging, and erosion and splitting of dorsal, pectoral, anal and caudal fins. Baseline values were determined for five wrasse species: goldsinny, Ctenolabrus rupestris; rock cook, Centrolabrus exoletus; corkwing, Crenilabrus melops; cuckoo, Labrus mixtus; and ballan, Labrus bergylta, held in a farm environment for 3 mo prior to transfer to salmon farms. The caudal fin was most affected by injury. The fin erosion index (FEI) was low in all species and below 0.6. The fin splitting index (FSI) was the most prominent index and was significantly higher in the caudal fin (FSI &gt; 2) compared with other fins (FSI &lt; 0.5), and also significantly higher in corkwing and rock cook compared with the other wrasse species. The FEI and FSI were also calculated for a group of ballan wrasse before stocking on a seawater farm, during the first winter and upon harvesting. There were no significant differences in the scores of fin erosion and fin splitting in any of the samples, although the indices were marginally poorer in winter.

A mortality event in wrasse species (Labridae) associated with the presence of viral haemorrhagic septicaemia virus

Viral haemorrhagic septicaemia (VHS) is an infectious disease of farmed and wild fish and has an extensive host range in both freshwater and marine environments. In December 2012, a wrasse population consisting of ballan, Labrus bergylta (Ascanius), corkwing, Symphodus melops (L.), cuckoo, Labrus mixtus L., goldsinny, Ctenolabrus rupestris (L.), and rock cook, Centrolabrus exoletus (L.), held at a marine hatchery in the Shetland Isles, Scotland, experienced a mortality event. Approximately 10000 wrasse were being held at the facility on behalf of an Atlantic salmon, Salmo salar L., aquaculture company prior to being deployed for the biological control of parasites on marine pen Atlantic salmon, aquaculture sites. Fish Health Inspectors from Marine Scotland Science initiated a diagnostic investigation, and subsequent diagnostic testing confirmed the site to be VHSV positive by qRT-PCR and virus isolation followed by ELISA. A VHSV genotype-specific qRT-PCR assay revealed that the isolates belonged to genotype III, the European marine strain of the virus. The virus genotype was further confirmed by nucleic acid sequencing of the partial nucleoprotein (N) and glycoprotein (G) genes followed by BLAST nucleotide searches. This study reports for the first time the detection of VHSV within multiple wrasse species and highlights the need for a comprehensive risk-based approach to the use of wrasse and other finfish species as biological controls within the aquaculture industry.

Attack intensity by two species of territorial damselfish (Pomacentridae) as estimates of competitive overlap with two species of wrasse (Labridae)

The intensity of interspecific territorial defense should be based upon the degree of competitive overlap. We tested this relationship in two territorial Caribbean damselfish (dusky, Stegastes adustus, and longfin, S. diencaeous) with intruders being the bluehead wrasse (Thalassoma bifascatus) and the slippery dick wrasse (Halichoeres bivittatus). Based on food habits, the slippery dick and the bluehead wrasse should have the same degree of competitive overlap to the two damselfish species. We also predicted that the larger slippery dick wrasse intruder would receive more aggression than the smaller bluehead wrasse intruder. Neither damselfish species distinguished between the two wrasses suggesting that they were ecologically equivalent. We also tested size differences within both species of wrasse and found that size had no influence on the aggression in the dusky damselfish. The longfin also did not show a size preference for the bluehead but did prefer to attack the larger slippery dick wrasse. In spite of the similarities between the dusky and the longfin damselfish and the similar food habits of the bluehead and the slippery dick wrasse, our results suggest that using intensity of interspecific territorial defense alone may not be an adequate measure of competitive overlap.

Wrasse (Labridae) as cleaner fish in salmonid aquaculture – The Hardangerfjord as a case study

Several species of wrasse (Labridae) are used as cleaner fish to remove salmon lice from farmed Atlantic salmon. We estimated the fishery and use of wrasse in Hardangerfjord. The estimated numbers of labrids used on salmon and rainbow trout farms varied between 86,000 and 251,000 from 2002–2006, but increased to as much as 1.1 million in 2009 and 2010. A total of 93,500 kg (around 1.54 million) labrids were reported landed during 2000–2010. Corkwing wrasse (Symphodus melops) was by far the most important wrasse species: 52% by weight and 56% by number. Ballan wrasse (Labrus bergylta) made up 34% by weight but only 14% by number (due to its larger size). The relative proportion of species between the different sampling locations in the fjord was significantly different, as was the condition factor of some species. Goldsinny wrasse (Ctenolabrus rupestris) had the slowest growth of the labrids in this study, and did not reach the minimum commercial catch size (11 cm) before they were 4–5 years old. Very few goldsinny caught were over that size. Corkwing reach commercial size in 1–2 years. The results of this study indicate that wrasse should be protected during the spawning season. Species such as goldsinny grow so slowly that they will most likely be collected several times in heavily fished areas but discarded because they are smaller than the minimum allowable size. This could be avoided through the use of modified traps with escape routes for undersized fish. This study represents a first step towards establishing a knowledge-based management plan for the wrasse fishery.