Does length-weight equation fit clupeid fishes? An evaluation of LWRs for six clupeids from Iran (Teleostei: Clupeiformes)

This study investigates length–weight relationships of six clupeid species (Alosa braschnikowi, Alosa caspia, Dussumieria acuta, Nematalosa nasus, Sardinella albella and Tenualosa ilisha) captured from three main water bodies of Iran (Persian Gulf, Oman Sea and Caspian Sea), to evaluate if the LWR parameters fit for these fishes having specific morphological characteristics. Based on the obtained results, i) the b value was influenced by recorded length (TL, SL, FL) and body shape, ii) it was within the expected range of 2.27–3.48, iii) length–weight relationships were highly correlated and significant (r2>0.82-0.98, P<0.001), and hence length-weight equations fit well with six clupeid species in the Iranian water bodies. The results presented here, would be useful for fishery biologists and fisheries stake-holders in the study area

Biological aspects of Sepia pharaonis in the Bahrekan waters (NW Persian Gulf)

The biological aspects of Sepia pharaonis was studied during years 2006-07. The studied area restricted to the Bahrekan in Khouzestan province covering the depths of 2 up to 25m. The sampling methods were gillnet and bottom trawl. A total of 310 specimens collected, of which there wasn’t found any cuttlefish in the study area from July to October (5 months). The collected samples were transferred to the laboratory ashore for further biological measurements consist of: Mantle length, Body weight, sex determination. Gonado-Somatic Index, and determination of Spermatophoric Index, Spawning season, Food preference, Maturity stages and chemical analysis for food value determination. The results showed that the overall sex ratio is about M:F= 2:1 with percentage of 67.41% for males and 32.50% for females. Males are significantly bigger than females with average mantle length (ML) of 233.3 and 269.3 mm for female and male, respectively; with body weight of 1102.3 and 1450.6 g. The mantle length body weight relationship was found W=0.001 ML 2.540 (R2= 0.92) Female as: W= 0.0015 ML 4797 (R2= 0.93) male From point of feeding, the food preferences results indicated that fish is considered as main food, crabs as minor food and other marine organisms such as bivalvia and gastropods as random food. The highest vacuity Index (CV) and empty stomachs was determined for March-April and the lowest value was is December. Also, the maximum GSI was estimated for March-April months in which showing coherrances with the lowest food preference. The maximum spermatophoricfilaments were 856 and 45 for male pharaoh cuttlefish with mantle length of 300 and 185 mm, and on the other hand this values for fecundity were estimated 1589 and 53 for female specimens with 254 and 198 mm mantle length. The spawning season occurs in April- March in which accompany with migration of pharaoh cuttlefish towards shallow waters. The fishing season would be in this period in w

Quagga Catshark Halaelurus quagga

The Quagga Catshark (Halaelurus quagga) is a poorly-known catshark recorded from very few specimens. It has a fragmented known distribution occurring off southwestern India, and around the Socotra Archipelago (Yemen). This small shark (reaching ~37 cm total length) occurs at depths of 54-300 m, but appears to be a mostly deep-water species. The development of intense deep-sea bottom trawl fishing off southwestern India where the species is most likely to be taken as bycatch is a concern. Its small size means that it would be discarded at sea, but survivorship would be low. There are currently no deep-sea fishing activities around the Socotra Archipelago. Declines off southwestern India are suspected, but the extent to which fishing is affecting the species there is not known. Despite some concern, the species is assessed as Data Deficient, with a urgent need to assess bycatch rates in the Indian deep-sea shrimp trawl fishery

Oman Bullhead Shark Heterodontus omanensis

The Oman Bullhead Shark (Heterodontus omanensis) is known only from central Oman and Pakistan. Although information is limited on its habitat and ecology, based on known habitats of other Heterodontus species it likely inhabits a rocky reef substrate, reducing its vulnerability to bottom trawl fisheries. However, there are trawl caught records of this species, and it is a potential bycatch of demersal line fisheries operating within its range, although no specific information is currently available. More information is required on its biology, abundance and full range, capture in fisheries and population trends. While the limited number of individuals recorded to date may suggest this species occurs in areas not fished heavily, there is currently insufficient information at assess how fisheries in the region are interacting with the species, and as such it is assessed as Data Deficient

Speckled Catshark Halaelurus boesemani

The Speckled Catshark (Halaelurus boesemani) is a relatively small (to 48 cm total length), data-poor catshark. It is known from a limited number of specimens collected from four locations along an ~900 km stretch of Somali coastline. It occurs on continental and insular shelves at depths of 29-91 m. Its entire distribution has been subject to at least four decades of unregulated commercial benthic trawling; shelf-occurring catsharks are very susceptible to capture in this fishing gear. The new Somali Fisheries Law bans benthic trawling, but it is suspected that past declines have already occurred given the long history of unregulated fishing across its entire range. Furthermore, enforcement of this new regulation will be a challenge. While specific data are lacking, a population size reduction of 30-50% is suspected over the past three generations (~45 years) based on actual levels of exploitation (bycatch) and the species is assessed as Vulnerable A2d. It is of concern that there have been no records since 1991, although it is acknowledged that research and monitoring have been limited in Somalia. Further investigation of this species is required to accurately define its range, biology, extent of catches in local fisheries and levels of declines. This assessment should be revisited as soon as this is available

Status of lanternfish stocks & exploitation in the Oman Sea

The fishing data of 1814 hauls during 393 fishing day s activity (2008-2010) in the Oman Sea were collected from F/V Fanoos-2, Fanoos-3, Fanoos-3 and Fanoos-4. It was found that the total mean CPUE of pelagic fishes were 1903 kg/h of which 1bout 1115 kg/h (58%) belong to lantern fishes and the others belong to hairtail, bigeye croaker and threadfin bream with a total CPUE of 788 kg/h considered as by-catch. Also, the maximum CPUE of lanternfish were in months January to March with values of 2473, 2160, 2784 and 2198 kg/h. A comparison between years 2008, 2009 and 2010 show that the CPUE of lanternfish were 1356, 1148 and 936 kg/h, and for by-catches were estimated 1034, 854 & 581 kg/h, respectively; in which it shows a descending trend. The distribution pattern maps for different seasons were prepared and it was found that the density is decreased from spring to winter with a descending trend of CPUE from 4900 to 2500 kg/h. The catch statistics show that the fishing season including towing depth, position of fishing ground and engine power are the main parameters affecting on amount of catch. Also a comparison between different vessels show that the highest amount of catch belonged to F/V Fanoos-2 with a CPUE of 2233 kg/h higher than the F/V Fanoos-3 with a CPUE of 1893 kg/h; and this value was estimated 1111 & 772 kg/h for vessels Fanoos-5 and Fanoos-6 as the lowest ones. On the other hand, the feeding regime of Pennahia anea was studied. A total of 188 specimens were seasonally collected; and different food indices such as VI, FI, FP, GaSI and food frequency were calculated. The annual mean GaSI was 1.1; and the average VI was 78.7% and the food preference was identified as Fishes (77%, main food), Crustaceans (19%, minor food) and Molluscs (4%). The Trichiurs lepturus (hairtails) were identified as the other main predator including Purple-back flying squid. The aging of Benthosema pterotum was done using sagitta otolith and the mean age was found about 349 days and it was proved that they have a short life span with less than one year old. The growth rate (mmd-1) of lanternfish has negative correlation with increase of body size and body weight

Smallbelly Catshark Apristurus indicus

The Speckled Catshark (Halaelurus boesemani) is a relatively small (to 48 cm total length), data-poor catshark. It is known from a limited number of specimens collected from four locations along an ~900 km stretch of Somali coastline. It occurs on continental and insular shelves at depths of 29-91 m. Its entire distribution has been subject to at least four decades of unregulated commercial benthic trawling; shelf-occurring catsharks are very susceptible to capture in this fishing gear. The new Somali Fisheries Law bans benthic trawling, but it is suspected that past declines have already occurred given the long history of unregulated fishing across its entire range. Furthermore, enforcement of this new regulation will be a challenge. While specific data are lacking, a population size reduction of 30-50% is suspected over the past three generations (~45 years) based on actual levels of exploitation (bycatch) and the species is assessed as Vulnerable A2d. It is of concern that there have been no records since 1991, although it is acknowledged that research and monitoring have been limited in Somalia. Further investigation of this species is required to accurately define its range, biology, extent of catches in local fisheries and levels of declines. This assessment should be revisited as soon as this is available

Ctenacis fehlmanni, Harlequin Catshark

The Harlequin Catshark (Ctenacis fehlmanni) is a small (to at least 52 cm total length) outer shelf dwelling catshark, known from 70 m to over 300 m depth off Somalia in the Arabian Sea. Little is known about the biology or ecology of this species. This poorly-known deep-sea shark occurs in an area where no deep-sea trawling fisheries take place and there are no other known threats. Due to the depth of occurrence and the lack of deep-sea fisheries in the region the species is assessed as Least Concern

Phylogeny of the Sepia pharaonis species complex (Cephalopoda: Sepiida) based on analyses of mitochondrial and nuclear DNA sequence data

The pharaoh cuttlefish, Sepia pharaonis Ehrenberg, 1831, is a commercially fished species found from Japan to East Africa. Previous morphological and genetic work (the latter based on the 16S rRNA mitochondrial gene) suggested that S. pharaonis is a species complex, but relationships within the complex remained unresolved. To clarify these relationships, we have sequenced an additional mitochondrial gene region (cytochrome oxidase subunit I) and a nuclear gene region (rhodopsin) from over 50 specimens from throughout the range of S. pharaonis. We have also added sequence data from two specimens of Sepia ramani Neethiselvan, 2001, collected in southeastern India. Sepia ramani is a species that is morphologically very similar to S. pharaonis, and there is some question regarding its status as a distinct species. Phylogenetic analyses of a dataset comprising all three-gene regions revealed a monophyletic S. pharaonis complex consisting of a western Indian Ocean clade, a northeastern Australia clade, a Persian Gulf/Arabian Sea (‘Iranian’) clade, a western Pacific clade and a central Indian Ocean clade. Relationships among these clades remain somewhat poorly supported except for a clade comprising the Iranian clade, the western Pacific clade and the central Indian Ocean clade. One S. pharaonis specimen was collected in the Arabian Sea, but was found to be a member of the western Indian Ocean clade, suggesting that gene flow between these regions has either occurred recently or is ongoing. Both specimens of S. ramani are members of the S. pharaonis complex, but their mtDNA haplotypes are not closely related – one is a member of the central Indian Ocean clade, while the other is rather distantly related to the northeastern Australia clade. We suggest that ‘S. pharaonis’ may consist of several species, but morphological work is needed to clarify species-level taxonomy within this complex

Phylogeography of the pharaoh cuttle Sepia pharaonis based on partial mitochondrial 16S sequence data

The pharaoh cuttle Sepia pharaonis Ehrenberg, 1831 (Mollusca: Cephalopoda: Sepiida) is a broadly distributed species of substantial fisheries importance found from east Africa to southern Japan. Little is known about S. pharaonis phylogeography, but evidence from morphology and reproductive biology suggests that Sepia pharaonis is actually a complex of at least three species. To evaluate this possibility, we collected tissue samples from Sepia pharaonis from throughout its range. Phylogenetic analyses of partial mitochondrial 16S sequences from these samples reveal five distinct clades: a Gulf of Aden/Red Sea clade, a northern Australia clade, a Persian Gulf/Arabian Sea clade, a western Pacific clade (Gulf of Thailand and Taiwan) and an India/Andaman Sea clade. Phylogenetic analyses including several Sepia species show that S. pharaonis sensu lato may not be monophyletic. We suggest that ‘‘S. pharaonis’’ may consist of up to five species, but additional data will be required to fully clarify relationships within the S. pharaonis complex