Substrate preference in age-0 red snapper, Lutjanus campechanus

We tested age-0 red snapper, Lutjanus campechanus, for sand or shell substrate preference in a circular tank (1.5 m diameter × 0.6 m deep). The test tank was divided into two equal areas of whole oyster shell or sand substrates. All trials were video taped for 20 to 25 min. Tapes were viewed on a monitor and locations of all fish recorded and timed with respect to substrate. Mean ± SE time on shell was 11.6 ± 0.5 sec (4 fish trial^–1) and 13.8 ± 1.1 sec (1 fish trial^–1). Mean ± SE time on sand was 9.7 ± 0.4 sec (4 fish trial^–1) and 8.9 ± 0.5 sec (1 fish trial^–1). Fish spent significantly more time on shell compared to sand substrate in four-fish trials (paired t-test, p < 0.10) and also in single-fish trials (paired t-test, p < 0.05). Shell substrate may offer increased food and shelter for age-0 red snapper compared to sand substrate. However, a preference for shell substrate in the natural habitat may occur only during the nursery period, because as fish grow (> 100 mm TL) in the late fall they probably outgrow the shell habitat.     

Effects of tag type on red snapper Lutjanus campechanus tag retention,growth and survival under hatchery conditions

Management of red snapper stocks is one of the most controversial issues in the Gulf of Mexico fisheries. Fish tagging programs can help to address many management issues if an appropriate tag is selected. In the study three types of tags were tested to determine tag retention and effects on red snapper growth and survival. Hatchery‐produced juveniles (43.7 ± 5.6 g) were either not tagged or given: internal anchor tags anchored in the abdominal cavity; passive integrated transponders (PIT) tags injected into the body cavity; or metal self‐piercing fish tags clamped around the dentary bone. Fish were stocked at 25 m^?3 in three replicate circular tanks/tag type, and fed a commercial feed for a 150 days period. Fish survival did not differ by treatment. Average weight gains after 150 days were similar. Tag retention differed by treatment (P = 0.0002), with 100% retention of PIT tags, 98.4 ± 2.8% retention of jaw tags, and 90.4 ± 1.6% retention of internal anchor tags. Loss of internal anchor tags occurred primarily within the first month. Inflammation was frequently observed at the internal anchor tag insertion site. Irritation and cell proliferation was sometimes observed in areas around the jaw tags.     

Evidence for spatial limitation of the bluestripe snapper Lutjanus kasmira in French Polynesia from parasite and otolith shape analysis

The study focused on small‐scale location and movement patterns of the bluestripe snapper Lutjanus kasmira on the north coast of Moorea (Society Archipelago, French Polynesia, south‐central Pacific). Juveniles of this species occur in the estuary, and adults occur widely in the lagoon, the outer slope and in the intermediate channel, where fish aggregate in large schools during daytime. While fish were all sampled within a few hundred metres, they exhibited significantly different parasite fauna and otolith shapes according to their locality: estuary, lagoon, channel and outer slope. While juveniles did not exhibit any parasites in the estuary parasitological and otolith‐shape data suggest that adults rarely move between their three adjoining habitats, and more interestingly that large aggregations in the channel are formed predominantly by resident individuals with limited local movement, including at night. Besides giving some information on the host biology, such findings may have application in local fisheries management.     

Susceptibility and tolerance of spotted seatrout, Cynoscion nebulosus , and red snapper, Lutjanus campechanus , to experimental infections with Amyloodinium ocellatum

Amyloodinium ocellatum is a parasitic dinoflagellate that infects warm-water marine and estuarine fishes and causes mortalities in aquaculture. Its life cycle consists of 3 stages: a feeding trophont that parasitizes the gills and skin where it interferes with gas exchange, osmoregulation, and tissue integrity; a detached reproductive tomont; and a free-swimming infective dinospore. We compared the susceptibility and tolerance of juvenile spotted seatrout, Cynoscion nebulosus, and red snapper, Lutjanus campechanus, to this parasite by individually exposing fish in 3-L aquaria (at 25 C and 33 practical salinity units) to several dinospore doses over different time periods and quantified the size and number of resulting trophonts. We estimated the trophont detachment rate and trophont size at detachment, the 24-hr dinospore infection rate, the dinospore 48-hr median lethal dose (LD(50)), and the trophont lethal load at the 48-hr LD(50). There were no significant differences in dinospore infection rates or dinospore lethal doses between spotted seatrout and red snapper; however, trophonts remained attached longer and attained a larger size in red snapper than in spotted seatrout. The trophont lethal load was significantly higher in spotted seatrout than in red snapper. A proposed model simulating the trophont dynamics reflected our experimental findings and showed that A. ocellatum reproductive success is linked both to the number of dinospores and the size of the trophont, factors that, in turn, are linked to the time the trophont spends on the host and the number of trophonts the host can tolerate.     

Mycoses in red snapper (Lutjanus campechanus) caused by two deuteromycete fungi (Penicillium corylophilum and Cladosporium sphaerospermum)*

We report two species of deuteromycete fungi (Penicillium corylophilum and Cladosporium sphaerospermum) concurrently infecting the swim bladder and posterior kidney and causing erratic behavior in two specimens of wild-caught, tank-held red snapper (Lutjanus campechanus). Lesions produced by both species infiltrated the immediately surrounding tissue and produced severe pathological changes; however, the infection apparently was not systemic. Only P. corylophilum grew in the initial culture from the swim bladder and only C. sphaerospermum grew in the initial culture from the kidney. Infection may have occurred upon penetration of a syringe to deflate the swim bladder. There was no horizontal transmission to 13 other specimens of red snapper held in the same tank. This suggests that these fungi are not primary pathogens. Injection of each species into various sites in the Gulf killifish, Fundulus grandis, failed to produce infections within 1 month, suggesting differences in susceptibility among species.     

Age estimation and otolith characteristics of an unusually old, red emperor snapper (Lutjanus sebae) captured off the Kimberley coast of north-western Australia

In October 2006, an unusually old, red emperor snapper, Lutjanus sebae , was captured using fish traps off the north coast of Western Australia. Despite being very old the specimen was not exceptionally large, measuring 516 mm fork length. Of particular note was the fact the specimen was female, as female L. sebae do not attain the large sizes at age of male fish. Interpretation of the sectioned sagittal otolith was used to estimate an age of approximately 40 years. This is the oldest recorded age for an individual L. sebae and further contributes towards the knowledge of the demography of this species. The advanced age recorded for this specimen also confirms the low rates of natural mortality for L. sebae and therefore low population productivity and supports the precautionary management arrangements for this species in north-western Australia.     

Spatial and Dietary Overlap Creates Potential for Competition between Red Snapper (Lutjanus campechanus) and Vermilion snapper (Rhomboplites aurorubens)

Understanding the complex nature of direct and indirect species interactions is a critical precursor to successful resource management. In the northern Gulf of Mexico fisheries ecosystem, red snapper (Lutjanus campechanus) and vermilion snapper (Rhomboplites aurorubens) are two commercially harvested species within a larger reef fish complex. These two species share similar habitats and diets; however, little is known about how these species partition habitat and dietary resources. In this study we examined the extent of spatial and dietary overlap between red snapper and vermilion snapper, and experimentally compared their feeding behavior. Field data from multiple gear types demonstrates that red snapper and vermilion snapper frequently cohabited reefs in the northern Gulf of Mexico, and Pianka’s niche overlap indices suggest significantly overlapping diets. Experimental manipulations show that red snapper are the dominant forager of the two species, as red snapper foraging alone ate more shrimp per fish than vermilion snapper in both the single species (p = 0.003) and mixed species (p = 0.02) treatments. In addition, red snapper ate significantly more shrimp per fish in the mixed species treatment than in the single species treatment (p = 0.04). Vermilion snapper shrimp consumption per fish did not differ significantly between mixed and single species treatments. Cumulatively, our results suggest that spatial and dietary overlap could lead to competition between red and vermilion snapper in the study area; however, conclusively determining the existence of such competition would require further research.     

Age, growth and reproduction of the humpback red snapper Lutjanus gibbus off Ishigaki Island, Okinawa

The humpback red snapper Lutjanus gibbus (Lutjanidae) is an important species for fisheries in the Kagoshima and Okinawan region of Japan. The present study estimated the age, growth and reproduction of this lutjanid species in the waters around Ishigaki Island, southern part of Okinawa. An opaque zone was formed on the otolith every year, and this formation correlated with their spawning season; these zones were identified as annual rings. Maximum ages of 21 and 24 years were observed for males and females, respectively. The von Bertalanffy growth parameters clarifying the age–fork length relationship were as follows: L _∞ = 390.5 mm, K = 0.210 year⁻¹ and t ₀ = −1.88 year for males, and L _∞ = 303.4, K = 0.256 year⁻¹ and t ₀ = −3.05 year for females. The main spawning season was estimated as between May and October, since greater values of gonadosomatic index for females as well as maturation oocytes and/or postovulatory follicles were observed during those six months.     

Multiplex genotyping of novel tetranucleotide microsatellites from a marine foodfish species crimson red snapper (Lutjanus erythropterus)

Crimson red snapper (Lutjanus erythropterus) is an important marine foodfish species in Asia with great potentials for aquaculture. We isolated nine polymorphic microsatellites, among which eight were tetranucleotide repeats, and one was CA‐microsatellite. The average allele number present in 48 individuals was 11.1/locus, ranging from three to 33. The expected heterozygosity ranged from 0.49 to 0.97 with an average of 0.74. Six of the nine markers conformed to the Hardy–Weinberg expectations. No pairwise markers showed the possibility of linkage. Protocols for two multiplex polymerase chain reactions (PCRs), each amplifying two and seven markers, respectively, were presented. The developed microsatellites and optimized multiplex PCRs will be useful for studying population structure of wild stocks and parentage assignment for cultured populations.     

Vibrios of the spotted rose snapper Lutjanus guttatus Steindachner, 1869 from northwestern Mexico

AIM: To characterize and identify vibrios present in wild and cultured juvenile snappers (Lutjanus guttatus) in northwestern Mexico. METHODS AND RESULTS: Spotted rose snapper juveniles were collected at four localities in northwestern Mexico. Bacteria were isolated from external lesions, kidney, liver, and spleen from cultured and wild caught organisms. In total, 280 isolates were obtained and fingerprinted with rep-PCR (GTG5). Nearly 93.2% of the strains belonged to the Vibrionaceae family. Species and genera identified were Photobacterium damselae subsp. damselae (76 strains), Photobacterium leiognathi (13), Vibrio sp. (24), Vibrio alginolyticus (12), Vibrio campbellii (19), Vibrio fortis (9), Vibrio harveyi (49), Vibrio ichthyoenteri (4), Vibrio mediterranei (4), Vibrio parahaemolyticus (1), Vibrio ponticus (2), Vibrio rotiferianus (22), and four potential new species. Conclusions: A wide diversity of vibrios was found in the external lesions and internal organs of both wild and cultured spotted rose snapper juveniles. In total, 12 species of vibrios and four potential new species were identified. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study on the vibrios present in the spotted rose snapper and therefore might serve as a basis for future studies and diagnosis.     

Carbon isotopes in otolith amino acids identify residency of juvenile snapper (Family: Lutjanidae) in coastal nurseries

This study explored the potential for otolith geochemistry in snapper (Family: Lutjanidae) to identify residency in juvenile nursery habitats with distinctive carbon isotope values. Conventional bulk otolith and muscle stable isotope analyses (SIA) and essential amino acid (AA) SIA were conducted on snapper collected from seagrass beds, mangroves, and coral reefs in the Red Sea, Caribbean Sea, and Pacific coast of Panama. While bulk stable isotope values in otoliths showed regional differences, they failed to distinguish nursery residence on local scales. Essential AA δ¹³C values in otoliths, on the other hand, varied as a function of habitat type and provided a better tracer of residence in different juvenile nursery habitats than conventional bulk otolith SIA alone. A strong linear relationship was found between paired otolith and muscle essential AA δ¹³C values regardless of species, geographic region, or habitat type, indicating that otolith AAs recorded the same dietary information as muscle AAs. Juvenile snapper in the Red Sea sheltered in mangroves but fed in seagrass beds, while snapper from the Caribbean Sea and Pacific coast of Panama showed greater reliance on mangrove-derived carbon. Furthermore, compound-specific SIA revealed that microbially recycled detrital carbon, not water-column-based new phytoplankton carbon, was the primary carbon source supporting snapper production on coastal reefs of the Red Sea. This study presented robust tracers of juvenile nursery residence that will be crucial for reconstructing ontogenetic migration patterns of fishes among coastal wetlands and coral reefs. This information is key to determining the importance of nursery habitats to coral reef fish populations and will provide valuable scientific support for the design of networked marine-protected areas.     

Validation of annual periodicity in otoliths of red snapper, <Emphasis Type="Italic">Lutjanus campechanus</Emphasis>

The periodicity of otolith growth increments (opaque and translucent zones) from adult red snapper (Lutjanus campechanus) was examined through a mark and recapture study (2005–2010), and laboratory holding of hatchery reared red snapper over a 2 year period (2002–2004). Wild red snapper (n = 295) were caught hook-and-line, marked with anchor tags, injected with oxytetracycline dihydrate (OTC), and released in the Gulf of Mexico 15–40 km south of Dauphin Island, Alabama. Marked fish were recaptured up to 2.8 years after release (n = 35) and sagittal otoliths were dissected, sectioned and examined under white and blue-violet light. The number of opaque growth zones past the OTC mark was compared to time at liberty for each fish and supported an annual periodicity of growth increment formation. Also, most (87%) of the hatchery reared fish showed two opaque zones that supported an annual increment formation rate. However, an unusual timing of opaque zone formation was shown for mark-recaptured fish. Based on known timing of OTC marking, otoliths from mark-recapture fish showed opaque zone formation from late summer (August) to early winter (December). This fall formation of opaque zones is in contrast to previous studies and its timing may relate to the end of spawning for this species.     

Construction of a fusion flagellin complex and evaluation of the protective immunity of it in red snapper (Lutjanus sanguineus)

Aims: The main aims of this study were to construct a bivalent subunit vaccine containing flagellin flaA gene and flagellin flaB gene from Vibrio alginolyticus strain HY9901 and to explore the potential application of the fusion protein FlaA‐(G₄S)₃‐FlaB as a vaccine candidate for red snapper (Lutjanus sanguineus). Methods and Results: Flagellin gene flaA and flaB of V. alginolyticus were linked by gene SOEing (gene splicing by overlap extension) technology. The expression of the fusion gene flaA‐(G₄S)₃‐flaB in Escherichia coli BL21(DE3) was confirmed by SDS‐PAGE. Western blot analysis showed that the fusion protein FlaA‐(G₄S)₃‐FlaB, which was purified by affinity chromatography on Ni‐NTA resin, had positive reaction with mouse anti‐FlaA serum and mouse anti‐FlaB serum, respectively. The immunoprotection of FlaA‐(G₄S)₃‐FlaB as a bivalent subunit vaccine was investigated in red snapper model by enzyme‐linked immunosorbent assay (ELISA) and challenge test. Red snapper vaccinated with FlaA‐(G₄S)₃‐FlaB produced specific antibodies and were highly resistant to infection by virulent V. alginolyticus. Conclusions: The fusion gene flaA‐(G₄S)₃‐flaB from V. alginolyticus strain HY9901 was cloned by gene SOEing and was expressed in E. coli. This fusion protein FlaA‐(G₄S)₃‐FlaB is a good protective antigen of V. alginolyticus and should be considered as an effective vaccine candidate against infection by V. alginolyticus in red snapper. Significance and Impact of the Study: Two flagellin genes, flaA and flaB, which are independent in structure and function, were first linked together by gene SOEing technology. The finding that red snapper did adequately respond to the fusion protein FlaA‐(G₄S)₃‐FlaB injection made it a promising candidate for vaccine treatment. To develop effective vaccine candidates against V. alginolyticus, more attention should be given to these immunogenic flagellins.     

Systemic infection of Kudoa lutjanus n. sp. (Myxozoa: Myxosporea) in red snapper Lutjanus erythropterus from Taiwan

A new species of Kudoa lutjanus n. sp. (Myxosporea) is described from the brain and internal organs of cultured red snapper Lutjanus erythropterus from Taiwan. The fish, 260 to 390 g in weight, exhibited anorexia and poor appetite and swam in the surface water during outbreaks. Cumulative mortality was about 1% during a period of 3 wk. The red snapper exhibited numerous creamy-white pseudocysts, 0.003 to 0.65 cm (n = 100) in diameter, in the eye, swim bladder, muscle and other internal organs, but especially in the brain. The number of pseudocysts per infected fish was not correlated with fish size or condition. Mature spores were quadrate in apical view and suboval in side view, measuring 8.2 +/- 0.59 microm in width and 7.3 +/- 0.53 microm in length. The 4 valves were equal in size, each with 1 polar capsule. Polar capsules were pyriform in shape, measuring 3.62 +/- 0.49 microm in length and 2.2 +/- 0.49 microm in width. Mild inflammatory responses or liquefaction of host tissue were associated with K. lutjanus n. sp. infection. The junction of shell valves appeared as overlapping, straight lines. The polar filament formed 2 to 3 coils. A general PCR (polymerase chain reaction) primer for Kudoa amplified the small subunit (SSU) rDNA sequences, and the amplified gene was sequenced. It was evident from the phylogenetic tree that the 3 strains tested, AOD93020M, AOD93028M and AOD93028B, were identical and belonged to the Kudoa SS rRNA subgroup. The evolutionary tree showed that these strains form a unique clade, at a distance from other Kudoa species and myxosporeans. The spore's morphological and ultrastructural characteristics, as well as the SS rDNA properties of the isolates, were also essentially identical and served to distinguish them from representative Kudoa. It is, therefore, proposed that the strains isolated from the diseased red snapper be assigned to a new species.     

Candidatus Renichlamydia lutjani, a Gram-negative bacterium in internal organs of blue-striped snapper Lutjanus kasmira from Hawaii

The blue-striped snapper Lutjanus kasmira (Perciformes, Lutjanidae) are cosmopolitan in the Indo-Pacific but were introduced into Oahu, Hawaii, USA, in the 1950s and have since colonized most of the archipelago. Studies of microparasites in blue-striped snappers from Hawaii revealed chlamydia-like organisms (CLO) infecting the spleen and kidney, characterized by intracellular basophilic granular inclusions containing Gram-negative and Gimenez-positive bacteria similar in appearance to epitheliocysts when seen under light microscopy. We provide molecular evidence that CLO are a new member of Chlamydiae, i.e. Candidatus Renichlamydia lutjani, that represents the first reported case of chlamydial infection in organs other than the gill in fishes.     

Characterization of 32 microsatellite loci for the Pacific red snapper, <Emphasis Type="Italic">Lutjanus peru</Emphasis>, through next generation sequencing

We developed a set of hypervariable microsatellite markers for the Pacific red snapper (Lutjanus peru), an economically important marine fish for small-scale fisheries in the west coast of Mexico. We performed shotgun genome sequencing with the 454 XL titanium chemistry and used bioinformatic tools to search for perfect microsatellite loci. We selected 66 primer pairs that were synthesized and genotyped in an ABI PRISM 3730XL DNA sequencer in 32 individuals from the Gulf of California. We estimated levels of genetic diversity, deviations from linkage and Hardy–Weinberg equilibrium, estimated the frequency of null alleles and the probability of individual identity for the new markers. We reanalyzed 16 loci in 16 individuals to estimate genotyping error rates. Eighteen loci failed to amplify, 16 loci were discarded due to unspecific amplifications and 32 loci (14 tetranucleotide and 18 dinucleotide) were successfully scored. The average number of alleles per locus was 21 (±6.87, SD) and ranged from 8 to 34. The average observed and expected heterozygosities were 0.787 (±0.144 SD, range 0.250–0.935) and 0.909 (±0.122 SD, range 0.381–0.965), respectively. No significant linkage was detected. Eight loci showed deviations from Hardy–Weinberg equilibrium, and from these, four loci showed moderate null allele frequencies (0.104–0.220). The probability of individual identity for the new loci was 1.46^?62. Genotyping error rates averaged 9.58%. The new markers will be useful to investigate patterns of larval dispersal, metapopulation dynamics, fine-scale genetic structure and diversity aimed to inform the implementation of spatially explicit fisheries management strategies in the Gulf of California.     

Molecular cloning, mRNA expression, and characterization of heat shock protein 10 gene from humphead snapper Lutjanus sanguineus

Heat shock protein 10 (HSP10) gene of humphead snapper (Lutjanus sanguineus), designated as ByHSP10, was cloned by rapid amplification of cDNA ends (RACE) techniques with the primers designed from the known EST sequence identified from the subtracted cDNA library of the head kidney of humphead snapper. Sequence analysis showed the full length cDNA of ByHSP10 was 529 bp, containing a 5′ terminal untranslated region (UTR) of 51 bp, a 3′ terminal UTR of 181 bp, and an open reading frame (ORF) of 297 bp encoding a polypeptide of 99 amino acids. Based on the deduced amino acid sequence, the theoretical molecular mass of ByHSP10 was calculated to be 10.92 kDa with an isoelectric point of 9.46. Moreover, chaperonins hsp10/cpn10 signature was found in the amino acids sequence of ByHSP10 by PredictProtein. BLAST analysis revealed that the amino acids of ByHSP10 had the highest homology of 88% compared with other HSP10s. Fluorescent real-time quantitative RT-PCR was used to examine the expression of ByHSP10 gene in eight kinds of tissues of humphead snapper after the challenge with Vibrio harveyi. There was a clear time-dependent expression pattern of ByHSP10 in head kidney, spleen and thymus after bacteria challenge. The expression of mRNA reached the maximum level at the time point of 9 h, 6 h and 24 h, respectively and then returned to control level in 36 h. The up-regulated mRNA expression of ByHSP10 in humphead snapper after bacteria challenge indicated that the HSP10 gene was inducible and might be involved in immune response. A phylogenetic tree was constructed based on the ORF nucleotide sequences of HSP10 for 30 species. The relatonships among them were generally in agreement with the traditional taxonomy which suggested that HSP10 genes could aid in the system classification research.     

Age,growth, and reproductive biology of blacktail snapper,Lutjanus fulvus,around the Yaeyama Islands,Okinawa, Japan

Age, growth, and reproductive characteristics of blacktail snapper, Lutjanus fulvus, which is a commercial fish species, were investigated using 322 specimens (40–332 mm in fork length) caught around the Yaeyama Islands, Okinawa, Japan. Spawning season was estimated to be from April to October, and spawning was confirmed around the full moon and the last quarter moon. Age determination using sectioned otoliths revealed that ages ranged from 0 to 34 years and the majority was ≥ 3 years. Parameters of the von Bertalanffy growth function were estimated to be L _∞  = 270 mm, k = 0.40, and t ₀  = ?0.48 years for females, and 257 mm, 0.44, and ?0.42 years for males. Initial growth was rapid during the first 3 years, attaining over 200 mm for both sexes, and then females grew larger than males. Sizes (ages) at the first sexual maturity were 225 mm (4 years) for females and 207 mm (3 years) for males. The wide range of age composition in catch with majority of ≥3 years old implied that the current fishing effort to harvest was not sufficiently large enough to collapse the stock immediately.