Caranx Ignobilis Research Articles

Quantifying the largest aggregation of giant trevally Caranx ignobilis (Carangidae) on record: implications for management

The giant trevally Caranx ignobilis (Forsskål) is an important apex predatory fish typically associated with coral reef communities. It is prized in recreational and commercial fisheries, yet little is known about its aggregation dynamics and susceptibility to fishing pressure. This study reports on a previously undocumented aggregation of mature giant trevally observed over a period of eight years (2010–2017) at Ponta do Ouro Partial Marine Reserve in southern Mozambique. The aggregation is one of the few recorded for this carangid in the western Indian Ocean and represents the first subtropical aggregation of giant trevally. The aggregation is also the largest recorded for this species, with up to 2 413 individuals representing an estimated biomass of approximately 30 tonnes. The size and predictability of this annual aggregation make it vulnerable to overexploitation and point towards the need for an appropriate conservation management strategy.

Estimation of CPUE and CPUA of three caught fish by bottom trawler in the Motaf fishing grounds, Bushehr Province, Persian Gulf, Iran

Seyed Hosseini SM, Paighambari SY, Pouladi M, Shabani MJ. 2018. Estimation of CPUE and CPUA of three caught fish by bottom trawler in the Motaf fishing grounds, Bushehr Province, Persian Gulf, Iran. Biodiversitas 19: 1434-1440. This study was conducted to estimate catch per unit effort (CPUE) and catch per unit area (CPUA) of Giant trevally (Caranx ignobilis Forsskål, 1775), Bigeye scad (Selar crumenophthalmus (Bloch, 1793), and Sulphur goatfish (Upeneus sulphureus (Cuvier, 1829). Sampling operations were done by a stern trawler in the Motaf fishing grounds located in the Persian Gulf during summer 2016. Overall, 36 hauls were done in two depths of 50-60 m and 60-70 m. In this research, the highest length frequencies of C. ignobilis, S. crumenophthalmus, and U. sulphureus were in the length classes of 56.5-61.5, 22-23.5 and 14-15.5 cm, respectively. The results of CPUE for C. ignobilis, S. crumenophthalmus, and U. sulphureus were 3, 0.159 and 0.078 kg h-1, while the results of CPUA were 45.03, 2.44 and 1.91 kg km-2, respectively. Also, CPUE values for mature and immature forms of C. ignobilis were 5.05 and 0.65 kg h-1, for S. crumenophthalmus were 0.2 and 0.07 kg h-1, and for U. sulphureus were 0.13 and 0.04 kg h-1, and CPUA values for C. ignobilis were 22.51 and 5.02 kg km-1, for S. crumenophthalmus were 22.03 and 10.95 kg km-1, and for U. sulphureus were 27.4 and 12.77 kg km-1 at the depths of 50-60 m and 60-70 m, respectively. Finally, it was concluded that effective fishing of C. ignobilis and U. sulphureus is affordable at depths above 60-70 m, and it was not different for S. crumenophthalmus at fishing depths.

Pioneer Attempt on Cage Culture of Giant Trevally, Caranx Ignobilis through Farmer Participatory Approach in Thiruthipuram Backwaters, Kochi, Kerala, India

Pioneer Attempt on Cage Culture of Giant Trevally, Caranx Ignobilis through Farmer Participatory Approach in Thiruthipuram Backwaters, Kochi, Kerala, India

Mercury Bioaccumulation in Tropical Mangrove Wetland Fishes: Evaluating Potential Risk to Coastal Wildlife.

The present study, aimed at observing the total concentration of mercury (Hg) in edible finfish species with an implication to human health risk, was carried out from the Setiu mangrove wetlands on the east coast of Peninsular Malaysia. Out of 20 species observed, the highest Hg concentrations were found among carnivores-fish/invertebrate-feeders, followed by omnivores and carnivores-invertebrate-feeders, while the lowest concentrations in herbivores. The Hg concentrations varied widely with fish species and body size, from 0.12 to 2.10mg/kg dry weight. A positive relationship between body weight and Hg concentration was observed in particular for Toxotes jaculatrix and Tetraodon nigroviridis. Besides the permissible range of Hg concentration up to 0.3mg/kg (cf. United States Environmental Protection Agency (USEPA)) in majority of species, the carnivore feeders such as Acanthopagrus pacificus, Gerres filamentosus, and Caranx ignobilis have shown excess amounts (> 0.40mg/kg flesh weight) that raising concerns over the consumption by local people. However, the weekly intake of mercury-estimated through the fish consumption in all three trophic levels-suggests that the present Hg concentrations are still within the range of Provisional Tolerable Weekly Intake (PTWI) reported by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Perhaps, a multi-species design for Hg monitoring at Setiu wetlands would be able to provide further insights into the level of toxicity transfer among other aquatic organisms and thereby a strong health risk assessment for the local communities.

Carbon, Nitrogen, and Mercury Isotope Evidence for the Biogeochemical History of Mercury in Hawaiian Marine Bottomfish.

The complex biogeochemical cycle of Hg makes identifying primary sources of fish tissue Hg problematic. To identify sources and provide insight into this cycle, we combined carbon (δ13C), nitrogen amino acid (δ15NPhe), and Hg isotope (Δ199Hg, Δ201Hg, δ202Hg) data for six species of Hawaiian marine bottomfish. Results from these isotopic systems identified individuals within species that likely fed from separate food webs. Terrestrial freshwater inputs to coastal sediments were identified as the primary source of tissue Hg in the jack species, Caranx ignobilis, which inhabit shallow marine ecosystems. Thus, coastal C. ignobilis were a biological vector transporting Hg from freshwater environments into marine ecosystems. Depth profiles of Hg isotopic compositions for bottomfish (excludung C. ignobilis) were similar, but not identical, to profiles for open-ocean pelagic fishes, suggesting that in both settings inorganic Hg, which was ultimately transformed to monomethylmercury (MeHg) and bioaccumulated, was dominantly from a single source. However, differences between pelagic fish and bottomfish profiles were attributable to mass-dependent fractionation in the benthos prior to incorporation into the food web. Results also confirmed that bottomfish relied, at least in part, on a benthic food web and identified the incorporation of deeper water oceanic MeHg sources into deeper water sediments prior to food web uptake and transfer.

Morphometric and molecular characterisation of Tenuiproboscis keralensis n. sp. infecting marine and brackish water fishes from the south-west coast of India with a note on morphological plasticity.

A new species of acanthocephalan infecting marine and brackish water fishes from the south-west coast of India is described. The parasite belongs to the genus Tenuiproboscis, and the fish hosts include Lutjanus argentimaculatus, L. ehrenbergii, Siganus javus, Epinephelus malabaricus, E. coioides, Scatophagus argus, Parascolopsis aspinosa, Caranx ignobilis, Gerres filamentosus and Lates calcarifer. The parasite inhabits mid- and hindgut regions and is characterised by an elongated, cylindrical, bulbous and posteriorly tapering metasoma and a claviform proboscis having 14-15 rows of 14-15 hooks each. Females larger than males, measured 3898.16-10,318.00μm (6430.00±1417.30) in length and 458.93-1435.68μm (929.81±250.39) in width. Males measured 3234.89-8644.20μm (5729.50±1176.60) in length and 388.30-1584.61μm (795.88±184.12) in width. Parasites recovered from different host species showed morphological/morphometric variations. However, principal component analysis (PCA) revealed significant overlapping of characters indicating their similarities. Proboscis profiling based on variations in size and position of hooks also yielded similar results. Further, in molecular phylogenetic analysis, parasites from different fish hosts formed a monophyletic clade with strong bootstrap support, again indicating their conspecific nature. These morphological/morphometric variations can be ascribed to differences in host species. Morphology and morphometrics in combination with PCA, proboscis profiling and molecular analysis suggest the present acanthocephalan parasite is different from other described species of Tenuiproboscis. Hence, it is considered as a new species and named T. keralensis n. sp. Prevalence, intensity and abundance of the parasite in different hosts are also discussed.

Biomagnification of total mercury in the mangrove lagoon foodweb in east coast of Peninsula, Malaysia

The combined analyses of total mercury (Hg) and stable isotopic (δ13C and δ15N) ratios were conducted to describe the food web pathways of dietary Hg, from basal food sources to benthic invertebrates and higher trophic level fish, and to determine if biomagnification of Hg is a persistent process in the food web in a mangrove creek in Setiu Lagoon. The study showed that Hg concentrations were relatively low in mangrove litter and sediment, but elevated gradually in higher trophic level consumers. Based on δ13C values, the variation of gastropod Hg concentrations are likely correspond with local dietary sources of Hg in sediments, while variations in bivalve Hg reflect their exposure to low Hg concentrations in the water body. The combination of depleted δ13C values and high Hg concentration in gastropods suggest that microbially produced Hg sources in mangrove sediments play an important role in benthic biotransfer pathways. The isotopic compositions of crustaceans demonstrate the importance of feeding behaviour in Hg bioaccumulation. High bioaccumulation of Hg occurred consistently in carnivorous fish species, particularly piscivorous Caranx ignobilis. The enriched δ13C of fish species reflects a small contribution of mangrove-derived organic carbon to the fish food web in the mangrove creek, accordingly the fish community may intake dietary sources of Hg via trophic relay or bioadvection, however further studies are needed to elucidate such factors. A positive relationship was found between Hg concentration and trophic level (derived from δ15N, trophic magnification factor of 1.5) even at low Hg concentration in the base of the food web, providing evidence for Hg biomagnification in the mangrove food web of Setiu lagoon. Whilst Hg concentrations in fish and commercial crabs did not present a risk for human consumption, the Hg concentration of Caranx ignobilis approached the official permitted level. In the future, there is a need for Hg biomonitoring designed to assess carnivorous fish in order to comprehensively assess the potential effects of human activities and land use around the upper reaches of the Setiu ecosystem.

Significant range extensions for two fish species at Pitcairn Island, South Pacific.

A baited videographic survey at Pitcairn Island has significantly extended the known range for two reef-fish species: blue-lined triggerfish Xanthichthys caeruleolineatus and greater amberjack Seriola dumerili, with an additional minor extension noted for giant trevally Caranx ignobilis. This highlights the importance of further research in this remote, poorly studied island group and provides evidence supplementing the understanding of oceanographic patterns in the South Pacific.

Displacement effects of heavy human use on coral reef predators within the Molokini Marine Life Conservation District

The impact of marine ecotourism on reef predators is poorly understood and there is growing concern that overcrowding in Marine Protected Areas (MPAs) may disturb the species that these areas were established to protect. To improve our understanding of this issue, we used acoustic telemetry to examine the relationship between human activity at the Molokini Marine Life Conservation District (MLCD) and the habitat use of five reef-associated predators (Caranx melampygus, Caranx ignobilis, Triaenodon obesus, Carcharhinus amblyrhynchos, and Aprion virscens). During peak hours of human use, there was a negative relationship (R2=0.77, P<0.001) between the presence of bluefin trevally (Caranx melampygus) and vessels in subzone A. No other species showed strong evidence of this relationship. However, our results suggest that during this time, the natural ecosystem function that the reserve was established to protect may be compromised and overcrowding should be considered when managing MPAs.

Movement patterns of reef predators in a small isolated marine protected area with implications for resource management

Reef predators play a critical role in maintaining the balance of marine ecosystems and are an important component of Hawaii’s recreational and commercial fisheries. In response to the increasing anthropogenic demands on these populations across the main Hawaiian Islands, the study of predator movements in marine protected areas has become a research priority. To this aim, we used passive acoustic telemetry to investigate the spatial and temporal movement patterns of five reef predator species: bluefin trevally (Caranx melampygus), giant trevally (Caranx ignobilis), green jobfish (Aprion virescens), whitetip reef sharks (Triaenodon obesus) and gray reef sharks (Carcharhinus amblyrhynchos) at the 31 ha Molokini Marine Life Conservation District (MLCD) off Maui, Hawaii (Lat: 20°37′56.70″N, Lon: 156°29′44.52″W) from November 13, 2013 to August 28, 2015. Our results indicate that the predator assemblage in the MLCD was dominated by teleost fishes during the day and sharks at night. Residency was variable across species, with bluefin trevally exhibiting the highest residency in the MLCD, green jobfish the lowest, and long-distance movements between the Molokini MLCD and the other islands of the Maui Nui Complex were common for gray reef sharks and giant trevally. These results indicate that despite its small size, the Molokini MLCD provides a high level of protection to resident species such as bluefin trevally. However, this MLCD is less effective at protecting more mobile predators such as green jobfish, gray reef sharks and giant trevally.

Movement patterns of two carangid species in inshore habitats characterised using network analysis

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 553:219-232 (2016) - DOI: https://doi.org/10.3354/meps11777 Movement patterns of two carangid species in inshore habitats characterised using network analysis Elodie J. I. Lédée1,2,*, Michelle R. Heupel1,3, Andrew J. Tobin1, Amos Mapleston1, Colin A. Simpfendorfer1 1Centre for Sustainable Tropical Fisheries and Aquaculture, College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia 2AIMS@JCU, Australian Institute of Marine Science, College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia 3Australian Institute of Marine Science, PMB No. 3, Townsville MC, Townsville, QLD 4810, Australia *Corresponding author: elodie.ledee@my.jcu.edu.au ABSTRACT: Carangids are important ecological components of coastal and reef habitats, in addition to their economic significance as a target species for some fishers. Despite these important ecological and economic roles, little information is available on the movement ecology of these species. Passive acoustic monitoring was used to track the movements of 16 giant trevally Caranx ignobilis and 20 golden trevally Gnathanodon speciosus in Cleveland Bay off the coast of Queensland, Australia. Long-term observations of behaviour and movement were recorded via a network of acoustic receivers, and a network analysis approach (a novel, alternative approach to conventional movement analysis) was applied to the collected data. Tagged individuals were present in the study region between 30 and 394 d (mean ± SD:166 ± 116 d) with a mean ± SE residency index of 0.7 ± 0.1. Notable inter-annual variation occurred with individuals that were detected on more days and more receivers, moved more frequently, and were more resident in some years than in others. In addition, movement patterns differed between species, with C. ignobilis being detected on fewer days by fewer receivers and moving less than G. speciosus. Network analysis revealed that a combination of factors including ontogeny, foraging niche, and habitat influences may explain differences in space use between the species. These results highlight unique behaviours between co-occurring and closely related species and enhance our understanding of animal interactions in inshore habitats. KEY WORDS: Acoustic monitoring · Caranx ignobilis · Gnathanodon speciosus · Information theoretic approach · Network analysis · Mixed model effects Full text in pdf format Supplementary material PreviousNextCite this article as: Lédée EJI, Heupel MR, Tobin AJ, Mapleston A, Simpfendorfer CA (2016) Movement patterns of two carangid species in inshore habitats characterised using network analysis. Mar Ecol Prog Ser 553:219-232. https://doi.org/10.3354/meps11777 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 553. Online publication date: July 14, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

Movements and space use of giant trevally in coral reef habitats and the importance of environmental drivers

Effective conservation of large predators requires a broad understanding of their ecology. Caranx ignobilis is a large marine predator well represented in coral reef environments, yet they are poorly studied. Passive acoustic monitoring was used to track the movements of 20 C. ignobilis at offshore reefs in the central Great Barrier Reef from 2012 to 2014. Using a modelling approach, temporal changes in movement patterns of C. ignobilis were explored to determine if individuals exhibited predictable movement patterns. The effects of biological and environmental variables on monthly space use, daily presence and hourly depth use were investigated to define any response to environmental changes. Caranx ignobilis typically remained at their capture reef with 98.8% of detections recorded at these locations. Individuals were recorded in the study site for periods from 9 to 335 days (mean = 125.9) with a mean residency index of 0.53, indicating movements away from the reef or out of detection range occurred on the scale of days. Inter-reef movements from only three individuals were recorded which coincided with the summer full moon so may have been related to spawning behaviour. Environmental drivers were correlated with daily presence and hourly depth use of C. ignobilis but had little influence on monthly space use. There was little or no effect of fish size on space use, presence and depth use. By improving the current understanding of movement patterns of this large teleost among individual coral reefs, the results of this study reveal that site attachment may be present and that environmental parameters play a role in observed movement patterns related to depth and presence. These data provide useful information for the development of management plans, particularly in relation to space-based protection.

Movements and foraging of predators associated with mesophotic coral reefs and their potential for linking ecological habitats

Marine predators will often perform diel and seasonal movements associated with specific habitats. In tropical areas, mesophotic coral reefs may be an important habitat type for many predators, but their use of these areas has rarely been investigated. We used results of acoustic telemetry and stable isotope analyses to investigate the diel and seasonal movements of Galapagos sharks Carcharhinus galapagensis and giant trevally Caranx ignobilis captured from a mesophotic reef (depth: 50 to 70 m) at an uninhabited Pacific atoll. All predators associated with mesophotic reefs performed horizontal and vertical movements over seasonal and diel time frames. Galapagos sharks performed reverse diel vertical movements, diving deeper during the night than during the day, while giant trevally displayed a mix, with some individuals performing regular diel movements (deep during the day, shallow at night) and others performing reverse vertical diel movements. Trevally used very shallow water during the summer spawning periods. The isotopic compositions of predators suggest they primarily forage in shallow reefs, although approximately 35% of resources came from mesophotic reefs. Similar to their variability in vertical movement strategies, giant trevally occupied a wide range of trophic positions, potentially due to individual specialization in diet and high levels of intra-specific competition. Mesophotic reefs may provide some prey to upper level predators but also serve as a refuge habitat. The frequent movements between habitats suggest that marine predators may function as significant trans- porters of nutrients, particularly from shallow to mesophotic reefs.

Postharvest handling practices and the development of histamine in Giant Trevally (Caranx ignobilis) fish: The case of Fiji

The study aimed at assessing the post-harvest handling practices of artisanal spear-gun fishers in Fiji and its impact in the development of histamine. The study employed in-depth interviews of artisanal fishers on their postharvest handling practices, and its relationships in the development of histamine in Giant Trevally (Aranxignobilis) fish. The Giant Trevally fish were further exposed to three different temperatures; 0°C, combination of 5°C and 28°C, and 28°C prior to histamine determination. Results revealed that spear-gun fishers do not normally ice their fish and rarely gut their catch during the fishing trips. However fish are only iced when received by middlemen and vendors once fish arrive at the landing sites, when stored in the recycled freezer containers. Fish are usually displayed un-gutted without ice on drained and tiled stalls, however used ice at the landing site are further reused to cool fish stored in the recycled freezer containers (above 5°C) alternatively every 2 h throughout the day for display on the counters (28°C) for sale. Any unsold fish are returned into the recycled freezer containers for sale the next day. Histamine determination revealed that after 35 h postharvest i.e. further storage at 0°C and at combination temperatures of 5°C and 28°C (recycled every 2 h) the histamine levels went below the Food Drug Administration (FDA) permitted levels (50 ppm). However, fish stored at 28°C had increased histamine concentration levels up to 193.2 ppm of 15 h post-harvest. The study demonstrated the importance of time and temperature control at postharvest handling of fish in tropical countries.

Stingrays as possible facilitators for foraging trevallies in a nearshore sandflat

Mixed-species associations are temporary aggregations of individuals of different species that are driven by improved foraging, anti-predator benefits, and host/ cleaner relationships (Morse 1977). Host/cleaner relationships are common among fishes, including between elasmobranchs and teleosts (Papastamatiou et al. 2007). However, the function of associations between teleosts and elasmobranchs for other purposes is poorly described (Heithaus et al. 2010). On 27 April 2013, in the waters of Petite-Terre, along the north shore of Terre de Bas (Guadeloupe archipelago, 16°10’23.10”N, 61°06’32.41”W), a ∼90 cm (disk width) southern stingray (Dasyatis americana) was observed (∼15 min) and filmed (102 s) in association with a ∼40 cm bar jack (Caranx ruber). The observation occurred at 340 pm in shallow waters (<1.5 m) over a sandflat that is adjacent to a coral reef ecosystem. Video footage shows the jack swimming above the ray and actively maintaining the association during periods when the ray stopped to forage or changed headings (Fig. 1a, see supplementary material). During extractive foraging by the ray, the jack was observed inspecting the sand plume expelled by the ray and striking at prey that were dislodged (Fig. 1b). It therefore appears that the jack was associated to the stingray to forage and may have been able to access otherwise unavailable resources. Similar commensal associations were observed in the Pacific Ocean by two of the authors (JJK and JPQ), where trevallies were associated with stingrays for foraging purposes : a t Cocos Is land (5°31 ’08 ’N, 87°04’18”W), involving the bluefin trevally (Caranx melampygus) and the black-spotted stingray (Taeniurops meyeni), and in the lagoon of Tetiaroa, French Polynesia (17°0’S, 149°33”W), where several associations between pink whiprays (Himantura fai) and both bluefin and giant trevallies (Caranx ignobilis) were observed. Stingrays were always alone, but up to three trevallies could be observed with a single ray. In several of these cases, trevallies were seen lunging in plumes created by rays. Although other benefits to trevallies (e.g. reduced predation risk) cannot be discounted, we hypothesize that rays constitute facilitators for foraging trevallies. As documented for other batoids such as bat rays (Myliobatus californica) and round stingrays (Urobatis halleri) (VanBaricom 1982; Heithaus et al. 2010), stingrays in coral reef ecosystems may facilitate other predators that take advantage of prey that are disturbed or excavated during ray foraging. Electronic supplementary material The online version of this article (doi:10.1007/s12526-014-0304-6) contains supplementary material, which is available to authorized users.

The first record, tagging and release of a neonatal whale shark Rhincodon typus in Taiwan.

On 27 October 2013, a Rhincodon typus was apparently chased by a group of Caranx ignobilis into nearshore waters near Green Island (Ludao), east of Taiwan. A fisherman brought it back to port where it was kept in a small sea pen until release. The R. typus was 78 cm total length, and was tagged and released on 29 October 2013.

Giant trevally spawning aggregation highlights importance of community fisheries management no-take zone

Location and timing of spawning aggregations for large teleost predators either remain elusive or constitute core-fishing sites in developing countries, limiting or confounding management actions for sustainable harvesting. In the Quirimbas Archipelago in northern Mozambique, limited artisanal fisheries catch data are available, and only emerging management plans are in place in scattered isolated locations. Artisanal fisheries, however, are the dominant fisheries sector in the region, employing a large proportion of the local population and contributing the main food source for consumption. Giant trevally (Caranx ignobilis) is a highly valued fish and consumed locally but data on giant trevally spawning locations is limited (Westernhagen 1974). This is a concern, given spawning aggregations are extremely susceptible to over fishing, but their functional role is imperative for maintaining ecosystem resilience. Within a community declared no-take zone on the eastern point of Vamizi island, a large aggregation of giant trevally were observed by scuba divers on December 15, 2013, two days prior to the full moon. The fish entered the shelf edge at ∼15–20 m depth from the adjacent deep-water reef channel during daylight hours (15:00) and two hours after high tide. The aggregation numbered >1,000 fish that were estimated to be approximately 80–100 cm total length and larger (Fig. 1a). Individuals were observed pair chasing and displaying color changes (silver to black; Fig. 1b). The fish remained in aggregation formation on the shelf for 1–2 min surrounding the divers before returning to the deep-water channel. Although the physical release of gametes was not observed, indirect evidence commonly used to infer spawning activity, indicate these fish were in the process of spawning

Hook selectivity of Giant Trevally (Caranx ignobilis) and Nakedbreast Trevally (Carangoides gymnostethus) (Carangidae) caught in the hook-and-line fishery off Negombo, Sri Lanka

In the present study, an attempt was made to quantify hook selectivity of two carangid species (Caranx ignobilis and Carangoides gymnostethus) which were predominantly caught in the hook-and-line fishery off Negombo, Sri Lanka. As the length frequency data of C. ignobilis and C. gymnostethus recorded by hook size were skewed towards the larger fish, a modification of Baranov-Holt method for gillnet selection was employed. For both species there were positive significant relationships (p&lt;0.001) between the hook size and optimal length while selection range was negatively related to hook size (p&lt;0.001). DOI: http://dx.doi.org/10.4038/sljas.v16i0.6712 Sri Lanka J. Aquat. Sci. 16 (2011): 11-26

Identifying the biodiversity of marine jacks (Carangidae) in the freshwater Taal Lake, Philippines using phenotypic features and mitochondrial DNA

Jacks, members of the genus Caranx (Perciformes: Carangidae), comprise economically-important marine fisheries across the world. In the Philippines, this valued fishery extends from the marine environment into a freshwater volcanic lake, Taal Lake. Two jacks, Caranx ignobilis (Forsskål, 1775) and C. sexfasciatus (Quoy and Gaimard, 1825), have long been reported from the lake, with recent molecular evidence alluding to genetic divergence between marine and freshwater populations. Here, a combination of phenotypic features and the mitochondrial Cytochrome oxidase b gene region were used explicitly to profile the taxonomic relationship between marine and freshwater specimens of C. ignobilis and C. sexfasciatus. Using molecular data from all known Philippine Caranx species, a partial phylogeny of the genus was reconstructed and contrasted to observed colouration, morphological and meristic features. Findings include the first report of C. papuensis, in Taal Lake; however, previous reports of C. sexfasciatus are not validated. Caranx ignobilis was confirmed present, yet several morphological features were unique to lake specimens, including red instead of yellow colouration of the lower jaw, anal fins, and caudal peduncle, and four instead of two canine teeth. Further, C. ignobilis sequence distance was 6.3% between marine and lake specimens, whereas C. papuensis distance was 0.2%. The combined molecular and phenotypic data suggest that Taal Lake C. ignobilis may represent an evolutionarily unique lineage. These data are significant for developing management strategies that have typically overlooked the ecological and evolutionary attributes of the jack fishery.

New record of two Indo-Pacific reef fish, Caranx ignobilis and Naso annulatus, from the Galapagos Islands

The first records of Caranx ignobilis and Naso annulatus in the Galapagos Archipelago are reported based on several sightings from its northernmost island, Darwin. For C. ignobilis this also represents its first record from the Tropical Eastern Pacific region, considerably expanding its geographical distribution. Vagrant status is proposed for both species in the Galapagos shore fish list.