Ciclo reproductivo y maduración sexual del pulpo almizclado Eledone moschata (Cephalopoda: Octopodidae) en el Mar Adriático norteño y central

Length-weight relationships, sex ratio, maturity patterns, reproductive outputs, fecundity and spawning period of the musky octopus Eledone moschata (Lamarck, 1798) in the northern and central Adriatic Sea are presented for the first time. Samples were collected on a monthly basis by commercial bottom trawls between October 2001 and June 2003. A total of 1552 specimens were analysed (779 males, 764 females, 9 undetermined). The overall sex ratio was close to 1:1, but during summer males were dominant. Length-weight relationships calculated for each sex and the whole sample showed negative allometric growth (bEn este documento se presentan por primera vez la relación talla-peso, proporción de los sexos, patrones de madurez, productos reproductivos, fecundidad y el periodo de desove del pulpo almizclado, Eledone moschata (Lamarck, 1798), en el Mar Adriático central y norte. Las muestras fueron recolectadas mensualmente en base a una red de muestreo de arrastre comercial entre octubre de 2001 y junio de 2003. Se analizaron un total de 1552 muestras (779 machos, 764 hembras y 9 indeterminados). La proporción sexual de la muestra total fue cercana a 1:1, pero el número de machos fue dominante durante el verano. La relación talla-peso por sexos y total de la muestra mostró un crecimiento alométrico negativo (

METODE ODREĐIVANJA DOBI I RASTA GLAVONOŽACA

Different methods used in age determination of cephalopods and their importance for assessment and management purposes for this group of marine organisms are described in the paper. Scientific investigations have proved that indirect methods (length frequency data) are not reliable enough and should always be accompanied with one direct method, although these methods are very demanding and time consuming. Today, statoliths are the most frequently used direct method for age estimation. These hard structures are proved to be very useful tool in age determination in squids (Teuthida). On the other hand, there are no standard age determination techniques for cuttlefishes and octopuses (Sepiida and Octopoda) and for these groups of cephalopods scientists are still searching for methods suitable for routine use.U radu su opisane različite metode određivanja dobi i rasta glavonožaca, kao i njihovo značenje za procjenu stanja i upravljanje zalihama gospodarski zanimljivih vrsta. Tijekom vremena istraživanja su pokazala da samo indirektne metode (dužinske učestalosti) nisu dovoljno pouzdane te da je najsigurniji način određivanja dobi kombiniranje indirektnih i direktnih metoda, unatoč tomu što direktne metode zahtijevaju mnogo uloženog rada i vremena. Od direktnih metoda danas se za očitavanje dobi najčešće primjenjuju statoliti, a napose dobri rezultati postignuti su kod lignji (Teuthida). Za sipe i hobotnice (Sepiida i Octopoda) ne postoje standardne tehnike za određivanje dobi i još uvijek se traga za metodama koje bi se rutinski primjenjivale za ove skupine glavonožaca

Nalaz vrste Neorossia caroli (Jouben, 1902) u srednjem Jadranu (hrvatske vode)

Two specimens of Neorossia caroli have been recorded for the first time in the central Adriatic Sea. They were caught in summer 2004 with a bottom-trawl net during a single tow at depths between 449 and 594 m in Croatian waters. Up to now N. caroli has never been found in the central Adriatic area. This finding represents a northernmost extension in the known range of the species N. caroli in the Adriatic Sea. Recorded specimens were both adult and mature males with mantle lengths of 42 and 37 mm. They counted 21 and 16 spermatophores, respectively. The measurements from both individuals are reported, including beak standard dimensions.Dva primjerka vrste Neorossia caroli po prvi put su nađena u hrvatskim vodama. Ulovljeni su u ljeto 2004. godine dubinskom povlačnom mrežom – koćom, tijekom jednog potega, na dubini između 449 i 594 m. Vrsta do sada nije zabilježena na području srednjeg Jadrana, te ulovljeni primjerci ujedno predstavljaju najsjeverniji nalaz ove vrste u Jadranskom moru. Nađene jedinke bile su spolno zreli mužjaci, dužine plašta 42 i 37 mm, u kojima je nađeno 21 odnosno 16 spermatofora. U radu se iznose osnovni morfomertijski podaci ulovljenih primjeraka, uključujući dimenzije kljuna

Influence of soak time on catch performance of commercial creels targeting Norway lobster (Nephrops norvegicus) in the Mediterranean Sea

Source at https://doi.org/10.1051/alr/2017035 .Creel catch performance is known to be affected by the soak time in many fisheries. If creels maintained their efficiency over longer periods, increase in soak time should lead to proportional increase in catch quantity. However, the exact shape of this relationship is unknown for creel fisheries targeting Norway lobster (Nephrops norvegicus). If it was known fishermen could adjust their fishing strategy accordingly and maximize their net earnings. We compared catch performance of creels targeting Norway lobster soaked for one and two days in the Adriatic Sea. Results were obtained for three crustacean species, Norway lobster (N. norvegicus), mantis shrimp (Squilla mantis), and blue-leg swimming crab (Liocarcinus depurator) and two fish species, poor cod (Trisopterus minutus) and blotched picarel (Spicara flexuosa). Doubling the soak time from one to two days did not double the catches and for Norway lobster no increase was found. For the other crustaceans, a slight but not significant increase was estimated. Catches of blotched picarel were significantly lower for the longer soak time, while the results were inconclusive for the poor cod

Upoznavanje značajki reproduktivne biologije, morfometrije i starosti vrste Chtenopteryx sicula (Cephalopoda: Chtenopterygidae) u Jadranu

The first record of the deep-sea species Chtenopteryx sicula is reported from the Adriatic Sea. Atotal of six specimens of this rare species were caught, with bottom trawl and pelagic trawl nets, in the scope of the Deep Sea Research of the bathyal fauna in the South Adriatic Pit in 2008 and 2010. Specimens were caught at depths down to 1200 m, therefore making it the deepest and northernmost finding of this species in the Mediterranean Sea. The dorsal mantle lengths of analyzed specimens ranged between 21 and 60 mm. Only in females, a visceral photophore on the ventral side of the inc sac was detected. Some new information on morphometric body and beak features was given in the paper, including the description of beak pigmentation. A number of increments in statoliths revealed that individuals were between three and five months old. A positive linear correlation between the length of statoliths and number of increments/age in days was detected. Macroscopic and histological samples of gonads proved that one specimen was sexually mature (August), four specimens were in stages of sexual maturation (May and August) and two were immature (March). The results indicated that the maturation process of the species in the South Adriatic Sea starts in spring and the full sexual maturity is reached during summer.U radu su opisani prvi nalazi dubokomorske vrste Chtenopteryx sicula u Jadranskom moru. Pridnenom i pelagičnom mrežom ulovljeno je ukupno šest primjeraka ove rijetke vrste u sklopu istraživanja dubokomorskih zajednica u južnojadranskoj kotlini 2008 i 2010. godine. Primjerci su ulovljeni na dubinama do 1200 m te predstavljaju najdublji i ujedno najsjeverniji nalaz ove vrste u Mediteranu. Dorzalna dužina plašta analiziranih jedinki kretala se od 21 do 60 mm. Samo u ženki nađeni su visceralni fotofori na ventralnoj strani vrećice sa crnilom. U radu su date nove informacije vezane uz obilježja kljuna, uključujući detaljan opis pigmentacije. Broj zona prirasta u statolitima ukazuje na starost jedinki između tri i pet mjeseci. Utvrđena je pozitivna korelacija između dužine statolita i broja zoni prirasta/starosti u danima. Makroskopski i histološki uzorci gonada potvrdili su da je jedna jedinka bila spolno zrela (kolovoz), četiri jedinke su bile u stadiju spolnog sazrijevanja (svibanj i kolovoz), a dvije su bile spolno nezrele (ožujak). Rezultati ukazuju na to da proces spolnog sazrijevanja ove vrste u južnom Jadranu počinje u proljeće, dok se puna spolna zrelost doseže tijekom ljeta

RASPODJELA I SASTAV POPULACIJE KUNJKE Arca noae U PAŠMANSKOM KANALU

Noah’s Ark shell Arca noae is an edible bivalve that is commercially exploited in the eastern Adriatic and is harvested primarily by SCUBA divers. There are no reliable data catch statistics data for this species nor there any data on distribution and population biology of exploited stocks, all of which are crucial for establishing sustainable level of exploitation. The objective of this research was to determine distribution and population structure of A. noae in one of the harvesting area — Pašman channel. Study was conducted in May 2008 using SCUBA visual census method at six transects. Although there are no previous data on distribution of A. noae in this area, low population density, length frequency distribution with domination of individuals smaller than 5 cm and sex ratio analysis all indicate that present level of harvesting is unsustainable.Kunjka (Arca noae) jestivi je školjkaš koji se komercijalno sakuplja u istočnom dijelu Jadrana, primarno metodom autonomnog ronjenja. Nema pouzdanih statističkih podataka o sakupljanju ove vrste kao ni podataka o raspodjeli i sastavu populacija iskorištavanih »stokova«, što je nužno za uspostavu održive razine eksploatacije. Cilj je ovog istraživanja bio određivanje raspodjele i sastava populacije vrste A. noae u jednom od područja sakupljanja — Pašmanskom kanalu. Istraživanje je provedeno u svibnju 2008. godine metodom vizualnog cenzusa na šest profila autonomnog ronjenja. Iako nema prethodnih podataka o raspodjeli vrste A. noae na ovom području, niska gustoća naseljenosti, histogram dužinskih frekvencija na kojem prevladavaju jedinke manje od 5 cm i omjer spolova upućuju na to da je postojeća razina eksploatacije neodrživa

Mesh sticking probability in fishing gear selectivity: Methodology and case study on Norway lobster (Nephrops norvegicus) and mantis shrimp (Squilla mantis) in the Mediterranean Sea creel fishery

Fish or crustaceans stuck in the fishing gear meshes can lead to operational problems in some fisheries and thereby affect theeconomic gain. However, mesh sticking probability has never been formally quantified as a part of the estimation of fishing gearsize selectivity. Therefore, this study developed a size selection model and estimation procedure that, besides the size dependentretention and escape probabilities, includes the size dependent mesh sticking probability. The new method was applied to quantify the size dependent retention, sticking and escape probabilities for mantis shrimp (Squilla mantis) and Norway lobster (Nephrops norvegicus) in creels with 41 mm square mesh netting. The mesh sticking probability was found to display a bell-shaped curvature with a maximum value for a specific carapace length and decreasing probabilities for both smaller and bigger individuals. For mantis shrimp the maximum sticking probability was found for 32.5 mm carapace length with a value at 13.5%, while 63.1% and 23.4% of that size were respectively retained inside the creels and escaped. For Norway lobster the maximum sticking probabilitywas 2% and occurred for 34.0 mm carapace length. The method and estimation procedure presented in this study might be applicable for quantifying mesh sticking probability as an integral part of future fishing gear size selectivity studies on other speciesand fisheries

Distribution and Population Structure of Greater Weever, Trachinus draco (Linnaeus, 1758.), in the Northern and Central Adriatic Sea

This study describes the distribution patterns and population structure of greater weever in the Adriatic Sea. Biological data were obtained during MEDITS surveys in the spring-summer period. The aim of this study is to provide recent data for better understanding of species biology and to create basis for fisheries management based on ecological approach