Occurrence of Lobotes surinamensis (Osteichthyes: Lobotidae) in the Mediterranean: Historical and recent data

This paper provides a review of the current status and historical distribution of Lobotes surinamensis in the Mediterranean Sea. Thirty two records were compiled for the period between 1968 and 2016, which shows that the species is in the Mediterranean much more abundant than previously understood.     

Appraisal of contaminants in sediments of the Inner Bristol Channel and Severn Estuary

In the inner Bristol Channel and Severn Estuary, most contaminated stations were in muddy, depositional areas of the estuary, particularly along the Welsh coast between the Rivers Taff and Usk, and also on the English coast between Avonmouth and Severn Beach. Some deeper areas, dominated by sand and mixed sediments, also showed contaminant concentrations in excess of those predicted from sediment texture, organic matter, and aluminium or iron concentrations.
Concentrations of lead, copper, chromium, nickel and zinc have decreased in the muddy sediments since the 1970s, but only lead has decreased in sand. With the exception of zinc, which is high in the Severn, trace element concentrations were comparable to those from other British estuaries.
Landward of the proposed barrage, contaminants are associated with the sub-estuaries and muddy areas at their confluence with the main estuary. Post-barrage effects on contaminants will be focused in these muddy areas. However, fine sediment deposition on what are now sandy areas would increase their contaminant burden unless calcium build-up from the resulting molluscan fauna has the antagonistic effect of contaminant dilution in the sediment.     

Cryopreservation of giant grouper Epinephelus lanceolatus (Bloch, 1790) sperm

The grouper, Epinephelus lanceolatus, is a vulnerable species of high economic value. An effective protocol was developed for the cryopreservation of E. lanceolatus by comparing different extenders produced by mixing various cryoprotectants (dimethyl sulfoxide, methanol and glycerol) and diluents (MPRS, TS‐2, TS‐19, Cortland and Hank's). Using computer‐assisted sperm analysis (CASA) and morphological analysis, the sperm motility and fertilization rates from post‐thaw sperm were comparable to untreated controls. The results revealed that MPRS (containing 12% DMSO) or TS‐19 (containing 12% DMSO), were the optimum extenders for protecting the sperm from cryo‐damage in liquid nitrogen. The post‐thaw sperm maintained high motility (90.61 ± 3.03%) and a fertilization rate (92.27 ± 2.43%) similar (P > 0.05) to fresh sperm (94.34 ± 4% and 94.10 ± 1.87%). This study is the first to report on the successful sperm cryopreservation of E. lanceolatus and provides an important tool for repopulating this species through aquaculture.     

Variation in populations of Littorina obtusata and L. mariae (Gastropoda) in the Severn Estuary

Populations of both species of flat periwinkle were examined at five discrete sites along the Severn Estuary, and at a marine site in Dyfed. The vertical distribution of the two species showed a clear partitioning of the shore – Littorina obtusata occupied the high/mid shore and L. mariae the low shore area. L. obtusata also extended further up the Severn Estuary than L. mariae. Maximum densities of both species were found in Milford Haven. Biometric investigations revealed intra and inter-specific differences in colour morphs, shell damage and size between populations. The possible influence of differential selection pressures at the various sites is discussed.     

Occurrence of dusky grouper Epinephelus marginatus (Lowe, 1834) in gulfs of northern Patagonia, Argentina

The occurrence of the dusky grouper Epinephelus marginatus in northern Patagonian Gulfs San Matías and Nuevo, Argentina, is recorded. This finding represents the southernmost record of the species for the southern hemisphere.     

The use of sectioned otoliths to age barramundi (Lates calcarifer) (Bloch, 1790) [Centropomidae]

The relationship between the number of rings present in sagittal otoliths and the age of barramundi, Lates calcarifer (Bloch, 1790) [Centropomidae], was investigated by examining cross sectioned otoliths of 37 tagged fish of known age between 1 and 5 years from the Johnstone River, north Queensland. Concentric rings were clearly visible in all otolith sections and were validated as annual marks. The technique was then used to estimate the age and calculate von Bertalanffy growth parameters for 70 barramundi from the Fitzroy River, central Queensland. Growth appeared to be rapid but variable in the first year; the von Bertalanffy growth parameters for length versus age were L =690 mm, K=0.53, t ₀= 0.003 years. October 1 was designated as the birth date. Whole otolith length, width and thickness were also approximated well by the von Bertalanffy equation. We suggest that examination of otoliths is a useful technique for ageing barramundi but note that further validation of the ageing method is still needed for fish older than six years.     

Occurrence of the rotifer,Habrotrocha cf. rosa Donner,in the purple pitcher plant,Sarracenia purpurea L., (Sarraceniaceae) along the eastern seaboard of North America

Sarracenia purpurea L. plants were studiedin seven bogsalong the eastern seaboard of the United States fromNew Jersey to Georgia. Water sampled from 225 leaveswas found to contain several invertebrates. A singlebdelliod rotifer, a form of Habrotrocha cf. rosaDonner very similar to that described by Bateman(1987) in S. purpurea in western Newfoundland,was identified in 70% of the leaves. Investigationsare in progress to examine the possibility that thisstrong association indicates H. cf. rosa isspecific to S. purpurea.     

Substantial northward range extension for Gephyroberyx darwini (Berycoidei, Trachichthyidae) in the western North Atlantic, possibly explained by habitat preference

Gephyroberyx darwini , herein reported northward to Browns Bank in the western North Atlantic, may inhabit rarely sampled hard substrata in northern temperate and boreal slope waters.     

Occurrence of the whitetip reef shark Triaenodon obesus at the Kermadec Islands,Southwest Pacific Ocean

ABSTRACT

Four observations of what was probably a single vagrant adult female whitetip reef shark Triaenodon obesus were made at Raoul and Meyer Islands, Kermadec Islands, New Zealand, over a 12 month period in 2014/15. This is the most southerly occurrence of the whitetip reef shark and ambient winter temperatures were close to the assumed thermal minimum for the species. The closest potential source population occurs at Minerva Reefs, about 598?km northwest of Raoul Island.     

Genetic population structure of red snappers (Lutjanus malabaricus Bloch & Schneider, 1801 and Lutjanus erythropterus Bloch, 1790) in central and eastern Indonesia and northern Australia

The genetic population structure of red snapper Lutjanus malabaricus and Lutjanus erythropterus in eastern Indonesia and northern Australia was investigated by allozyme electrophoresis and sequence variation in the control region of mtDNA. Samples were collected from eight sites in Indonesia and four sites in northern Australia for both species. A total of 13 allozyme loci were scored. More variable loci were observed in L. malabaricus than in L. erythropterus . Sequence variation in the control region (left domain) of the mitochondrial genome was assessed by RFLP and direct sequencing. MtDNA haplotype diversity was high ( L. erythropterus , 0·95 and L. malabaricus , 0·97), as was intraspecific sequence divergence, ( L. erythropterus , 0·0–12·5% and L. malabaricus , 0·0–9·5%). The pattern of mtDNA haplotype frequencies grouped both species into two broad fisheries stocks with a genetic boundary either between Kupang and Sape ( L. malabaricus ) or between Kupang and Australian Timor Sea ( L. erythropertus ). The allozyme analyses revealed similar boundaries for L. erythropterus . Seven allozymes stocks compared to two mtDNA stocks of L. malabaricus including Ambon, which was not sampled with mtDNA, however, were reported. Possible reasons for differences in discrimination between the methods include: i) increased power of multiple allozyme loci over the single mtDNA locus, ii) insufficient gene sampling in the mtDNA control region and iii) relative evolutionary dynamics of nuclear (allozyme loci) and mitochondrial DNA in these taxa. Allozyme and haplotype data did not distinguish separate stocks among the four Australian locations nor the central Indonesian (Bali and Sape locations) for both L. malabaricus and L. erythropterus.     

First records of the parthenogenetic Surinam cockroach Pycnoscelus surinamensis (Insecta: Blattodea: Blaberidae) for Central Europe

Sixteen species of cockroaches have been reported for Austria so far. This study is the first record of the parthenogenetic Surinam cockroach, Pycnoscelus surinamensis (L.) for Austria (and thus Central Europe). The species is natively distributed in Indo‐Malaysia but has been unintentionally introduced in many, mainly tropical, countries throughout the world. Sequencing the DNA barcoding region revealed that all Austrian P. surinamensis samples had the same haplotype, which they shared with samples from the United States of America, Guyana and French Polynesia, indicating that all these samples/populations belong to the same clonal lineage. Even though in temperate regions, the occurrence of P. surinamensis is currently limited to greenhouses, we advocate proper monitoring of the populations with respect to global warming and the expected increasing independence of this species from greenhouses that comes along with it.     

Length-weight relationship of 16 fish species from the Negro River basin (Amazonas state,Brazil)

This study aimed to estimate the parameters of length-weight relationship for 16 freshwater fish species that inhabit the Aracá and Demeni Rivers, which are two tributaries of the Negro River (Amazonas state, Brazil). The fishes were sampled using gillnets (15 × 2 m, mesh size 30–120 mm between opposite knots), during 6 days each year, in April 2016, November 2018 and April 2019. The gillnets were placed in the river twice each day; in the morning (5–9 a.m.) and in the evening (5–9 p.m.), with a standardized time of 4 hr. Measurements were taken for standard length (SL – 0.1 cm precision) and total weight (TW – 0.01 g precision). The parameters a and b of the equation W_T = a.L_T^b were estimated. This study also provides new data on of maximum lengths for six species, namely, Argonectes longiceps, Hemiodus atranalis, Chalceus erythrurus, Astrodoras asterifrons, Trachydoras steindachneri and Acarichthys heckelii.