The respiratory mechanisms of the dusky flathead, Platycephalus fuscus (Platycephalidae, Scorpaeniformes)

The respiratory mechanisms of a shallow-water, marine and estuarine flathead, Platycephalus fuscus C. & V. are described. Morphological and behavioural adaptations enabling respiration while the fish is buried in fine, unconsolidated sediments are investigated and related to the ecology of the species.     

The presence or absence of Rogadius asper (Cuvier 1829) in Australia (Scorpaeniformes: Platycephalidae)

Ichthyological Research -     

Microanatomy of the digestive tract and accessory organs of the Japanese flathead (Inegocia japonica Cuvier, 1829) (Scorpaeniformes,Platycephalidae)

The Japanese flathead, Inegocia japonica Cuvier, 1829 is a commercially important fish in small-scale coastal fisheries in Thailand; however, an explanation of its digestive biology is missing. This study describes the digestive tract and accessory organs of I. japonica, using morphological and histological methods. The fish (10 individual fish, 24.5 ± 0.98 cm in total length) were obtained from Libong Island, Thailand. Integrated morphological and histological data showed that the digestive tract was composed of oesophagus, stomach, pyloric caeca and intestine, with accessory organs. All digestive tracts consisted of four layers, including mucosa, submucosa, muscularis and serosa. Two stomach regions were identified (cardiac and pyloric stomachs). Several clusters of gastric glands were identified in the cardiac stomach. Each gland was a unicellular structure. The apical surface of this gland contained the vacuolar cell. The intestine was lined with a simple columnar structure with goblet cells that was similar to pyloric caecum. Goblet cells were rare in the anterior intestine, in contrast to the posterior intestine where goblet cells were abundant. The numerous of hepatocyte was mostly observed in the liver, whereas an exocrine acinar cell of pancreas was also identified. The results of our observations provided the first information of the digestive tract of I. japonica and can be applied to advanced study, such as physiology and histopathology.     

Life history of an unusual marine fish: survival, growth and movement patterns of Hippocampus guttulatus Cuvier 1829

The life history of the long‐snouted seahorse Hippocampus guttulatus was characterized using mark‐recapture data collected within a focal study site and catch data from 53 additional sites in the Ria Formosa coastal lagoon, southern Portugal. Population structure in benthic habitats was characterized by high local densities (0·3–1·5 m^?2), equal sex ratios and few juveniles <70 mm. Adult H. guttulatus maintained small (19·9 ± 12·4 m²), strongly overlapping home ranges during multiple reproductive seasons. Recruited (benthic) juveniles exhibited significantly lower site fidelity than adults. A Ford‐Walford plot of standard length (L_S) at time t against L_S measured during the previous year from tagged juveniles and adults led to estimates of the von Bertalanffy parameters K = 0·571 and L_∞ = 197·6 mm. The growth rate of planktonic juveniles (inferred from previous studies), was greater than predicted by the von Bertalanffy model, providing evidence of an ontogenetic shift in growth trajectory. The instantaneous rate of natural mortality, M, ranged from 1·13 to 1·22 year^?1(annual survival rate = 29·4–32·2%). Sexes did not differ in movement, growth or survival patterns. On average, H. guttulatus measured 12·2 ± 0·8 mm at birth. Planktonic juveniles recruited to vegetated habitat at 96·0 ± 8·0 mm (0·25 years), had mature brood pouches (males only) at 109·4 mm (0·49 years), began maintaining home ranges and reproducing at 125–129 mm (0·85–0·94 years), and lived for 4·3–5·5 years. Early age at maturity, rapid growth rates, and short generation times suggested that H. guttulatus may recover rapidly when direct (e.g. exploitation) and indirect (e.g. by‐catch and habitat damage) effects of disturbance cease, but may be vulnerable to extended periods of poor recruitment.     

Redescriptions of Dampierosa daruma Whitley 1932 and Erosa erosa (Cuvier in Cuvier and Valenciennes 1829) (Teleostei: Synanceiidae)

Ichthyological Research - Dampierosa daruma Whitley 1932 and Erosa erosa (Cuvier in Cuvier and Valenciennes 1829) (Synanceiidae) were redescribed on the basis of both primary type and non-type...     

Reproduction,growth and mortality of the exploited sillaginid,Sillago ciliata Cuvier, 1829

The goal of this study was to examine the age and size composition, growth, reproductive biology and mortality of Sillago ciliata Cuvier, 1829 in one of the largest estuarine commercial fisheries in south‐eastern Australia. The study also aimed to present a qualitative comparison of latitudinal variations in some of these characteristics along the eastern Australian coastline. The sampled population contained fish aged up to 10 years with a maximum size of 39.2 cm fork length (L_F), and was dominated by 1–5 year olds. Sexual divergence in both the age and size structure of the population was recorded. Female S. ciliata grew slightly faster and attained a greater maximum size (L_∞ = 33.79 cm L_F, k = 0.50 year^?1 and t₀ = ?0.57 years) than males (L_∞ = 29.73 cm L_F, k = 0.49 year^?1 and t₀ = ?0.67 years). Females also matured at a significantly larger size (19.13 cm) and older age (1.63 years) than males (size: 17.07 cm, age: 1.10 years). Reproductive activity was highest between September and March. There were no differences between males and females in terms of mortality rate; the estimated total population, natural and fishing mortality rates were Z = 0.64, M = 0.42 and F = 0.22, respectively. Although these mortality rates suggest that S. ciliata in the Clarence River are relatively resilient to current rates of exploitation, regular monitoring of their commercial and recreational catch as well as their population structure is recommended in order to maintain sustainable fisheries. Potential latitudinal shifts in the spawning period, age structure and growth of S. ciliata along eastern Australia were also revealed.     

Fatty acid profiles of Trachinus radiatus Cuvier, 1829 (Perciformes‐Trachinoidei,Trachinidae)

The goal of this study was to analyse the fatty acid (FA) profiles of the streaked (starry) weever (Trachinus radiatus), a prized food fish in the countries of its distribution. Fish (N = 20) were sampled in July 2011. Location: 42.761019°N, 17.765090°W; Adriatic Sea, Elaphite Islands near Dubrovnik, Croatia, at 5–10 m depth using longline hooks; body length ranges: 24.1–47.2 cm, weight ranges: 120–960 g. Morphological species determination was genetically confirmed (Folmer region of COI gene). Biochemical analysis of T. radiatus muscular tissue (filet) revealed average ± SD dry matter of 252.3 ± 14.8 g/kg w.w.; moisture of 747.7 ± 14.8 g/kg w.w., and ash of 28.0 ± 6.9 g/kg w.w. Intramuscular crude protein content exceeded the total lipid (TL = 11.9 ± 4.0 g/kg w.w.) content approximately 17.7 fold. Unsaturated FA (UFA) was higher than saturated FA (SFA), with a predominance of polyunsaturated FA (PUFA). The ω3:ω6 ratio was 4.9:1, respectively. Among individually determined fatty acids, the PUFA 22:6n3 (DHA) was highly present (29.99 ± 2.75% TL) followed by a relatively high 20:5n3 (EPA) content. There was 25 fold higher EPA content than of substrate αLNA, and a 15.5 fold higher DHA content to DPAn3. Such ratios indicate that besides trophic ingestion, FA bioconversion elongase/desaturase synthesis pathways toward ω3 PUFA in Weevers could be highly efficient.     

Length‐weight relationships of three fish species from Jask mangrove protected area in northern coastline of Gulf of Oman (Hormozgan,Iran): Liza klunzingeri (Day, 1888), Cociella crocodilus (Cuvier, 1829) and Platycephalus indicus (Linnaeus, 1758)

This study presents length‐weight relationships (LWRs) of Liza klunzingeri (Day, 1888), Cociella crocodilus (Cuvier, 1829), Platycephalus indicus (Linnaeus, 1758) belonging to two Families (Mugilidae and Platycephalidae) from northern coastline of Gulf of Oman (Hormozgan province). Samples were collected by artisanal trawl and beach seine (both with 11 mm effective mesh size) monthly during 2010 to 2015. The presented models were highly significant (p < 0.01) with a reliable coefficient of determination (R² > 0.90) that provides a reliable basic information for ichthyologists and fisheries scientists.     

Age estimation and specific growth pattern of boxlip mullet,Oedalechilus labeo (Cuvier, 1829) (Osteichthyes,Mugilidae), in the eastern Adriatic Sea

The main objective of this study was to investigate boxlip mullet, Oedalechilus labeo (Cuvier, 1829), a species that lives in open, oligotrophic and stenohaline waters, exhibits slower growth rates and has a longer life span than other mugilids. A total of 1662 specimens ranging from 2.2 to 24.4 cm TL were obtained by beach seine in the eastern Adriatic Sea. The overall sex ratio was unbalanced in favour of females (1.0 : 1.3) and differed statistically from the expected 1 : 1. The reproductive season extended through summer and autumn. All specimens above 15 cm TL were sexually mature. Length‐weight relationship for males was TW (g) = 0.010 × TL (cm)^2.975 and TW (g) = 0.009 × TL (cm)^3.014 for females. The age study comprised 150 (38.5%) males, 192 (49.4%) females, and 47 (12.1%) immature O. labeo, for a total of 389 individuals. Age of the fish was determined by scale readings, with the maximum age of 10⁺ observed for both sexes. A predominance of age classes 1⁺ and 2⁺ (71.0%) in the total catch was noted. Parameters of the von Bertalanffy growth equation for combined samples were: L_∞ = 25.93 cm, k = 0.192 year^?1 and t₀ = ?1.427 year. The growth parameters showed that males grew at a slightly lower rate than females. The size and age frequency distributions of both sexes were not significantly different. When compared to other mugilids, O. labeo reaches the lowest maximum body length and has a relatively slower growth and a longer life span.     

Redescription of Platycephalus angustus Steindachner 1866 (Teleostei: Platycephalidae), a valid flathead in northern Australia and New Guinea

The platycephalid Platycephalus angustus Steindachner 1866, which has not appeared in recent publications, is recognized as valid and redescribed on the basis of 24 specimens collected from northern Australia and New Guinea. This species is easily separable from other congeners in having a combination of the first dorsal fin usually with two small anterior isolated spines, dorsal and anal soft rays usually 13, orbit relatively small (orbital diameter 11.2–21.5 % HL), postorbital region long (postorbital length 55.5–67.8 % HL), interorbital space wide (interorbital width 7.3–17.3 % HL), suborbital region narrow (suborbital width 4.7–7.2 % HL), vomerine tooth rows tending to increase in number with growth, with 2–4 rows in 106–184 mm SL specimens and a single broad band of numerous rows in larger specimens, teeth present on the dorsal surface of the premaxilla anterolaterally on the edge of the upper jaw in specimens ca. 76 mm SL or longer, and 3–5 dark brown to black bands and spots on its caudal fin. As the stated type locality, Surinam, is considered erroneous, and the holotype appears to have been lost, a neotype is designated with a type locality northeast of Darbilla Creek, Millingimbi, Northern Territory, Australia.

     

Age,growth, and maturity of the Indian flathead Platycephalus indicus in the waters around Okinawa-jima Island,Japan

Ichthyological Research - Indian flathead Platycephalus indicus (Platycephalidae) is an important fishery resource in tropical and subtropical waters. However, there have been few studies of its...     

Review of the genusBembras Cuvier, 1829 (Scorpaeniformes: Bembridae) with description of three new species collected from Australia and Indonesia

The bembrid genusBembras Cuvier is reviewed. Five species,B. japonica Cuvier,B. adenensis Imamura & Knapp and three undescribed species, were assigned to the genus. Type species of the genus,Bembras japonica is redescribed on the basis of 36 specimens including the holotype, and three new species,B. macrolepis, B. longipinnis andB. megacephala, previously misidentified asB. japonicus, are also described on the basis of specimens collected from Australia and Indonesia.Bembras macrolepis differs from its congeners by having large body scales, a long pectoral fin with 17–19 rays and a dark blotch on slightly upper portion to middle of margin, 14–15 anal-fin rays, small head and orbit, and caudal fin with a broad vertical dark band near posterior margin.Bembras longipinnis is distinguished from other members of the genus by having a slightly long pectoral fin with 17–19 rays and lacking a small black blotch near tip of upper rays, caudal fin with a large dark spot most intense in lower lobe, 1–2 gill rakers on upper gill arch, 13–14 anal-fin rays, slightly elong ated head and small orbit.Bembras megacephala is characterized by the following combination of characters: caudal fin with several irregular narrow vertical dark bands, small orbit, pectoral fin with 19–20 rays and lacking a small black blotch near tip of upper rays, head elongate, 2–4 gill rakers on upper gill arch, 15 anal-fin rays and small body scales. A key separating the five species ofBembras is given.     

Population dynamics of the long-snouted seahorse (Hippocampus guttulatus Cuvier, 1829) in the Mar Menor coastal lagoon

A 10-year monitoring program was developed to quantify the population dynamics of the long-snouted seahorse population in the Mar Menor coastal lagoon. Based on 985 underwater visual censuses, we estimated the long-snouted seahorse (Hippocampus guttulatus Cuvier, 1829) population size in the Mar Menor lagoon and its reduction in size in the last decades, as well as the effect of eutrophication crises in 2016 and 2019 on the species. The annual recruitment for the 2013–2020 period was estimated by comparing the relative abundance of early seahorse life stages in the ichthyoplankton. The density ranged from 0.0458 specimens/m³ at the beginning of the sampling period to 0.0004 at the end, showing a statistically significant difference between the three analyzed periods (H_gl=2 = 14.0, p = 0.001). The long-snouted seahorse population from the Mar Menor lagoon exemplifies the impact of fishing activities and human pressure, especially euxinic episodes and habitat destruction. As a result of this, the Mar Menor population has decreased from several million specimens to a few thousand, in only three decades. This species showed considerable resilience, the seahorse population began to recover once fishing activity stopped. In contrast, the long-snouted seahorse showed high vulnerability to habitat loss and an episodic flooding event. Adult seahorses showed preferences for highly complex habitats, especially Caulerpa prolifera–Cymodocea nodosa mixed meadows and habitats of high complexity and anthropogenic origin, such as harbors, jetties, or breakwaters. In contrast, juvenile seahorses preferred monotonous seabeds with low complexity, such as the sandy beds that are characteristic of the Mar Menor lagoon littoral.