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An analysis of historical landing data of some pelagic species caught by purse seines in the Aegean Sea
(Ege Univ, Fac Fisheries, 2021) Tosunoglu, Zafer; Ceyhan, Tevfik
The fishing activity with purse seines in the Aegean Sea accounts for almost half of the pelagic fish excluding anchovy (Engraulis encrasicolus Linnaeus, 1758) in Turkey. In this study, we aimed to analyse the catch amounts of some important pelagic species caught by Aegean purse seiners between 1973 and 2019. While mid-1990s are the most captured years for the European pilchard (Sardina pilchardus Walbaum, 1792) in Aegean Sea and also Turkish Seas, this amount has decreased at the level of 10000 mt in the mid-2000s and remained similar amounts up to now. Though European pilchard was the most caught species in the Aegean until 2011, this has changed in favour of anchovy in the last decade. Recently, almost all pelagic species such as mackerel (Scomber scombrus Linnaeus, 1758), chub mackerel (Scomber japonicus Houttuyn, 1782) and bogue (Boops boops Linnaeus, 1758) have been caught from the Aegean Sea in Turkey. In the study, the production of these species in the historical period was tried to be associated with the regulations implemented with circulars and notifications, and the problems preventing the sustainable use of these species that were caught by purse seiners were determined and solutions were proposed for the future.
Analysis of Long and Short Terms Fishery Landings of Koycegiz Lagoon (Turkey)
(Central Fisheries Research Inst, 2019) Tosunoglu, Zafer; Saygi, Hulya
In the present study, we analysed long and short terms fishery landings of Koycegiz Lagoon recorded by Dalko (Dalyan Fishery Cooperative) for sustainable fishery. These time series are long-term (1974-2016) data which include monthly short-term (2012-2016) in the more recent years. A combination of Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA) were used to determined characteristics of the lagoon. Grey mullets are the most abundant species accounting for 86% of the total biomass of the landing for the 43-year period, followed by Common carp, European eel, Sea bass, Gilthead sea bream and others. PCA values are highly correlated grey mullets, European eel and Sea bass for P1, Striped sea bream, Gilthead sea bream, Carp and other for PC2, respectively. The first discernible cluster comprised Gilthead sea bream, Striped sea bream, Sea bass, other and European eel. The second included carp and the third cluster was represented by Grey mullets. Koycegiz Lagoon is the only lagoon where landings did not show a decreasing trend for a long time in Turkey due to the fact that lagoons have been strictly protected by special rules and owing to the fishing strategies developed by Dalko.
Are the Fishers of Lake Marmara Willing to Pay for a Sustainable Fishery Management?
(Central Fisheries Research Inst, 2017) Bodur, Huriye Goncuoglu; Ayan, Melike; Ozcan, Mehmet; Tosunoglu, Zafer
This study, analyzing the sustainable use of fisheries in Lake Marmara, was conducted in Golmarmara, a town of Manisa. The study makes use of contingent valuation method to calculate the monetary values which fishers who are actively using the lake are willing to pay in order for a sustainable use of the lake. For this purpose, data were collected through face-to-face interviews made with 55 of the 130 commercial fishers active in the lake. Variables affecting fishers' acceptance of extra payment were found to be: knowing the lake is a natural protection zone, education, experience in fishing, income, vessel ownership and retirement status. Of the 55 fishers interviewed, 96% (53 fishers) believe that the lake is under a threat in terms of fisheries while 50 fishers (90%) are willing to pay for the sustainability and improvement of the fisheries in the lake (18,681 TRY ($6,912) in total per year). The calculated willingness to pay (WTP) per fisher averages 143.7 TRY per year. With this study, fishers have proven that they will take on responsibility in creating the required data and budget to establish a sustainable fisheries management and prepare management plans.
Aspects of biology of the deep-water pandalid shrimp Plesionika martia (A. Milne-Edwards, 1883) from Sigacik Bay (eastern Mediterranean)
(Tubitak Scientific & Technical Research Council Turkey, 2012) Kocak, Cengiz; Ozbek, Murat; Tosunoglu, Zafer
Some aspects concerning the reproduction, growth, and population dynamics of Plesionika martia were studied. Individuals were collected monthly between May 2008 and April 2009 during surveys conducted using a commercial trawl vessel. Samples were collected from Sigacik Bay (Aegean Sea, eastern Mediterranean) at depths ranging from 494 to 550 m. A total of 2110 individuals (766 males and 1344 females) were caught during these monthly surveys. The carapace length (Cl,) of the males ranged from 12.4 to 22.1 mm, and in females the CL ranged between 11.5 and 24.9 mm. The values of both CL and weight in females consistently exceeded that of males throughout the year. Although ovigerous females were observed throughout the year, the main reproductive period is suggested to be from May to December. In all groups examined, the values of allometric coefficient b were less than 3. Estimates of the Von Bertalanffy growth parameters were L-Y = 26.25 mm and k = 0.38 year(-1) in females, and L-Y = 23.63 mm and k = 0.49 year(-1) in males.
Assessing Codend Mesh Selectivity: Comparing Diamond and Square Mesh Codend in the Red Sea Shrimp Trawl Fishery of Saudi Arabia
(MDPI, 2024) Santucci, Ronald Grech; Tosunoglu, Zafer; Cilbiz, Mehmet; Charles, Santhosh Kumar; Gireesh, Sheeja; Kadengal, Sirajudheen Thayyil; Dimech, Mark
This study assessed catch composition, size selectivity, and fishing efficiency of demersal trawls targeting penaeid shrimp species in the Red Sea. It first compared the currently used diamond mesh codends in two fishing areas, Al Qunfudhah and Jazan, and then compared alternative square mesh codends to diamond mesh codends in Jazan. A total of 33 valid hauls were conducted in 2023, yielding 10,869 kg of total catch. The results showed that the square mesh codend significantly improved size selectivity, particularly for Penaeus semisulcatus and Metapenaeus monoceros, with L50 (50% retention length) values closer to their size at first maturity. The fishing efficiency indicators revealed a reduced retention probability for undersized individuals with square mesh codends. Additionally, bycatch discard rates decreased, indicating potential benefits for ecosystem conservation. This study suggests incorporating square mesh codends into fishery management regulations to enhance size selectivity and reduce bycatch during Red Sea shrimp trawling. Establishing a legal minimum landing size requirement is recommended to complement these efforts and promote sustainable fishing practices.
A blue crab (Callinectes sapidus Rathbun, 1896) individual with partial albino: A case report
(Ege Univ, Fac Fisheries, 2019) Ilkyaz, Akin Turker; Tosunoglu, Zafer
In this study, a partial albino finding of a blue crab specimen sampled in Koycegiz Lagoon (Mugla, Turkey) is presented. the carapace part of the individual was in normal colour and pseudo-albinism was observed in most of the extremities of the specimen.
A blue crab (Callinectes sapidus Rathbun, 1896) individual with two carapace widths: a case report
(Scientific Technical Research Council Turkey-Tubitak, 2019) Ilkyaz, Akin Turker; Tosunoglu, Zafer
In this study, findings of morphological deformation observed on a blue crab sampled in Koycegiz Lagoon (Mugla, Turkey) are presented. The deformation is in the left lateral spine. It has been observed that this spine, which normally should have been one, developed as two independent spines. Due to this abnormality observed in the individual, the individual has two carapace widths.
Can Shifting Codend Mesh Shape and Mesh Size Increase the Size Selectivity of Red mullet (Mullus barbatus) in the Black Sea?
(Central Fisheries Research Inst, 2018) Kaykac, M. Hakan; Zengin, Mustafa; Tosunoglu, Zafer
More than half of the landing (70%) of Red mullet (Mullus barbatus) in Turkey is provided from the Black Sea, which is almost all (96%) with bottom trawls. The effect of demersal trawl codend mesh shape and size on the selectivity of Red mullet in the Black Sea was investigated. Selectivity trials were conducted in August 2014 on a commercial trawl boat with conventional (40D), 36 and 40 mm square mesh (36S and 40S) and turned mesh codends (40T90). Data were collected using the covered codend method with a total of 21 valid hauls and selection parameters were obtained by fitting a logistic equation using maximum likelihood method. The L-50 value was found to be very low at 9.79 cm in the 40D trawl codend, while the L-50 value of 40S (11.89 cm) and 36S (10.59 cm) codends was obtained 21.5% and 8.2% better compared to the 40D, respectively. According to the traditional trawl codend, a L-50 value increase of 5.1% was observed in 40T90 (10.29 cm). Although all these values are below the Minimum Landing Size of the species, changes to the traditional mesh, especially in the shape of the mesh, can lead to significant improvements in size selectivity.
THE CATCH CHARACTERISTICS OF A SET LONGLINE FISHERY IN THE FOCA SPECIAL ENVIRONMENTAL PROTECTION AREA, TURKEY
(Wydawnictwo Akad Rolniczej W Szczecinie, 2020) Guclusoy, Harun; Ondes, Fikret; Tosunoglu, Zafer
Background. Fisheries activities are rarely documented in the marine and coastal protected areas in Turkey. This study aimed to determine the catch composition of set longline fishery in the Foca Special Environmental Protection Area (Turkey), and to understand the effects of factors (e.g., bait type, hook size, and soak time) on the catch per unit effort (CPUE) and the size of species caught. Material and methods. Samples were collected by small-scale fishing boats in 2007 at depths ranging from 1 to 50 m. Kruskal-Wallis test was used to understand if the CPUE changes depended on the fishery specific factors (hook size and bait type). Mann-Whitney U test was used to test if CPUE changes depended on sampling seasons (autumn and summer). Chi-square test was used to determine whether hook size influenced the body size of two commonly caught species. Results. The following 25 fish species were caught, Diplodus sargus, Sparus aurata, Diplodus vulgaris, Boops boops, Lithognathus mormyrus, Oblada melanura, Conger conger, Trachurus sp., Spondyliosoma cantharus, Pagellus erythrinus, Pagrus pagrus, Dentex dentex, Sciaena umbra, Scorpaena scrofa, Belone belone, Serranus sp., Myliobatidae gen. sp., Muraena helena, Sarpa salpa, Diplodus annularis, Coryphaena hippurus, Diplodus puntazzo, Chelidonichthys lucerna, Scomber japonicus, and Dicentrarchus labrax. The most commonly caught species were white seabream, Diplodus sargus and gilthead seabream Sparus aurata. The hook size and bait type were important factors that influenced the CPUE. Moreover, the hook size significantly influenced the body size of caught white seabream and gilthead sea bream. Conclusions. The discard level was low in the set longline fishery in the Foca Special Environmental Protection Area. We recommend using 12 sized hooks rather than 13 to reduce the discards of the main target species in the Foca SEPA. Nevertheless, this also needs an economic assessment, and also identification and use any incentives to promote the shift in the use of larger size hooks. Minimum size limits to be set in the fisheries legislation and alternative bait use studies were also recommended.
Comparison of selectivity of the trawl codends for whiting (Merlangius merlangus euxinus) in the Black Sea
(Ege Univ, Fac Fisheries, 2019) Zengin, Mustafa; Akpinar, Ilkay Ozcan; Kaykac, M. Hakan; Tosunoglu, Zafer
A large part of the total whiting (Merlangius merlangus euxinus) fishing in the Black Sea is carried out with the traditional bottom trawl nets along the coast of Turkey. Diamond mesh shape with 40 mm mesh size (40D) has been used in the codends of these trawls. in this study, the traditional trawl codend (40D) and square-mesh codend with different size (36S and 40S) were compared for whiting size selectivity in August 2014. Selectivity data were collected by using a covered codend method and analysed taking between haul variations in to account. the selectivity parameters were estimated by using CC2000 software. Results showed that commercially used 40D trawl codend is not selective enough to release immature of whiting. However, the net change in square mesh (36S and 40S) instead of a diamond-shaped (40D) mesh significantly improved the mesh selectivity for whiting. the 40S trawl codend is even higher than the first maturity size (L-M50) with a length at fifty percent retention (L-50) of 15.74 cm. in conclusion all square mesh codends with different mesh size tested here supplied appropriate selection considering minimum landing size (MLS) of whiting.
Comparison of technical measures in the Aegean Sea to support harmonization of fisheries management policies
(Pensoft Publishers, 2022) Dereli, Hakki; Unal, Vahdet; Miliou, Anastasia; Tsimpidis, Theodoros; Trompouki, Ifigeneia; Tosunoglu, Zafer; Alexopoulos, Konstantinos
The Aegean Sea features an important archipelago in the Eastern Mediterranean, consisting of 60 inhabited islands, more than 1400 uninhabited islands, about 60???70 commercial marine taxa, along many vulnerable species. Fisheries are mainly coastal and are exploited by Greek and Turkish fishers. The multi-species and multi-gear fisheries operate within each country???s 6-nautical mile territorial sea and in the international waters of the Aegean Sea. As the fisheries resources are currently declining in this region, it is clear that current management initiatives are ineffective and would benefit from a new regime aiming to improve the state of the commercial marine resources. This study offers a comparative analysis of certain fishing gear technical measures applied by Greece and Turkey in the Aegean Sea. Identified differences can provide clear and helpful insights for decision-makers for the development of a new and productive management approach in Aegean waters. The fishery regulations were shown to be highly variable, sharing few similarities and stressing many more differences, thus rendering the current management of the shared fish stocks unsustainable. The resources of both states would greatly benefit from the harmonization of management measures focusing on an ecosystem approach to fisheries, and incorporating fishers as stakeholders.
The effect of mesh size and cod end material on the mortality and yield of the rose shrimp, Parapenaeus longirostris (Lucas, 1846) (Decapoda, Penaeidae) in the Turkish beam trawl fishery
(Brill Academic Publishers, 2006) Deval, Mehmet C.; Ates, Celal; Bok, Tomris; Tosunoglu, Zafer
Mortality and yield parameters of the rose shrimp, Parapenaeus longirostris were compared with length frequency data collected from the beam trawl fishery in the Sea of Marmara. Von Bertalanffy parameters were estimated as L infinity=16.28 cm and K=0.490 year(-1). The rates of total (Z), natural (M), and fishing (F) mortalitiy were calculated as 2.83, 0.97, and 1.86 for a 32 mm PE (polyethylene) cod end. The Z and F rates for two other cod ends, 32 mm PA (polyamide) and 36 mm PA, were, respectively, 2.13 and 1.16, versus 1.57 and 0.60. A study on the relative yield per recruit shows that maximum yield can be obtained at an exploitation rate (E) of 0.53, 0.52, and 0.45, respectively, for 32 PE, 32 PA, and 36 PA cod ends, whereas the current E values are 0.65, 0.54, and 0.38. Consequently, 32 mm PE and PA cod ends cause overfishing pressure on the stock of P. longirostris.
Effect of steel wire and claw size on the sea snail (Rapana venosa) catch in a Black Sea beam trawl fishery
(Scientific Technical Research Council Turkey-Tubitak, 2018) Kaykac, Muharrem Hakan; Gumus, Aysun; Zengin, Mustafa; Suer, Serdar; Ruzgar, Melih; Van, Ayse; Tosunoglu, Zafer
The effects of the claw size used on the shoes of the traditional sea snail beam trawl and the effect of the steel wire used between the shoes on catching efficiency were investigated on the Samsun coast of the Black Sea. A traditional beam trawl with steel wire and with a claw length of 5.5 cm (T) was compared to modified beam trawls with steel wire (M1) and without steel wire (M2) with a claw size of 0.5 cm. The operations were performed as T-M1 and then T-M2 hauls using the dual parallel towing method. There was no significant difference in the amount of target species in the comparison of T (70.12) and MI (63.23) according to the average catch per unit effort (CPUE, kg h(-1)) values obtained (P =0.399). In the T-M2 comparison, 49% higher CPUE value was achieved with the T (77.37) beam trawl and there was a significant difference in terms of targeted species (P = 0.002). As a result, it was observed by underwater observations that steel wire on the beam trawl had a negative effect on the ground, and it was found that the bycatch ratio with the T beam trawl was higher than that with the modified beam trawl.
Effects of Lunar Phases and Other Variables on CPUE of European Pilchard, Sardina pilchardus, Caught by Purse Seine in the Eastern Mediterranean
(Central Fisheries Research Inst, 2021) Tosunoglu, Zafer; Ceyhan, Tevfik; Gulec, Ozlem; Duzbastilar, Faik Ozan; Kaykac, Muharrem Hakan; Aydin, Celalettin; Metin, Gulnur
European pilchard Sardina pilchardus (Walbaum, 1792) is one of the most dominant small pelagic landed by purse seine in Turkey as well as Mediterranean. in this study, we aimed to identify relationships between the seasonally adjusted CPUE and changes of the sea surface temperature (SST), fishing area, moon phase, and light used in the purse seine fishery to understand the impact of changes on the CPUE of pelagic fishes, especially S. pilchardus, by a total of 214 operations in Izmir Bay, Aegean Sea. The effect of the parameters on the Sardine CPUE, expressed in terms of kg (haul day)(-1), was examined by means of the Generalized Additive Modelling (GAMs) techniques. The CPUE values for S. pilchardus were between 0 - 16 800 kg (haul day)(-1) and the mean CPUE was 1 844.3 +/- 176.6 kg (haul day)(-1). The smallest median was 441 kg (haul day)(-1) for full moon and the differences between the CPUE values of lunar phases were statistically significant (p<0.05). Furthermore, there is a linear relationship between CPUE and SST. in conclusion, the CPUE varied under hydrographic variables mostly SST for sardine purse seine fishery in the Aegean Sea.
Evaluation of the lagoon fishery on occupational health and safety
(Ege Univ, Fac Fisheries, 2019) Koken, Seda; Ceyhan, Tevfik; Tosunoglu, Zafer
Lagoons are important parts of the fishery sector as the areas where the entry and exit of waters are used under controlled conditions. At the present time, the protective and preventive measures have been started to be applied against the hazards and risks in the fields of occupational health and safety. Lagoon fisheries are among the fishery activities (including purse seine fishing, scuba fishing) in marine and coastal waters that are coded as 03.11.01 in the NACE code in occupational health and safety in the workplace hazard classes declaration and are classified as dangerous. in this study, it is aimed to examine the fishery in terms of occupational health and safety. For this reason, randomly 3 lagoons were determined among the 6 lagoons that continue their active activities on the coasts of the Aegean Sea between October 2017 and April 2018, 92 surveys were interviewed face to face. the 97% of the fishermen surveyed were male and 3% female employees. 90% of D1, 74% of D2 and all D3 employees are primary school graduates. the rate of health examinations of employees before work is 29% in DI, 97% in D2 and 17% in D3.The 25% of the employees in D1, 29% in D2 and 26% in D3 have knowledge about occupational accidents and occupational diseases. in terms of occupational accidents in lagoon, cutting, crushing, fracture-dislocation, suffocation and head injuries were frequently determined as 50%, 19%, 9% and 6%, respectively. the pier platforms where occupational accidents are most prevalent in lagoon barrier trap are not safe by employees, 44% in D1, 11% in D2 and 35% in D3.
How fish populations in Lake Bafa (Western Anatolia) respond to ecological shifts
(Wiley, 2024) Kurtul, Irmak; Kaya, Cueneyt; Kaykac, Hakan; Ilhan, Ali; Duzbastilar, F. Ozan; Tosunoglu, Zafer; Sari, Hasan M.
Long-term biodiversity monitoring is crucial for freshwater ecosystems as it enables the detection of even subtle changes and biodiversity trends, guiding conservation efforts and ensuring the sustainability of these vital habitats. Despite becoming more commonly considered in the field of freshwater ecology and biological invasions, studies using long-term time series from T & uuml;rkiye's freshwater resources have remained scarce. To assess the availability of data and ultimately present a baseline for future efforts, we combined published museum records and samples from recent field studies from the highly anthropogenically-altered Lake Bafa in Western Anatolia covering the period 1958-2019. Lake Bafa has a very diverse aquatic ecosystem, providing habitat for both freshwater and saltwater species, and is one of the allottees in T & uuml;rkiye's inland fish production. In the current study, we investigated how fish populations in Lake Bafa were affected by environmental changes and examined changes in taxonomic and functional diversity of non-native species over time. The analyses revealed-concomitant to an increase in native marine and freshwater species richness-an increase in non-native species richness over time. Non-native species did not interfere with native species' niche space, whereas applied models indicate that in this highly altered ecosystem, foremost temperature and salinity shaped the fish community over time, limiting the impacts of non-native species. These results have implications for the fishery of the lake, which includes highly valuable catadromous fish species, highlighting the value and importance of collecting long-term data in T & uuml;rkiye to better understand both invasion dynamics and changes in the naturality of Turkish ecosystems. These findings further underline the importance of long-term data to create new management strategies for the lake and to start restoration processes, thus improving fisheries management.
Interactions Between Sea Turtles and Fishing Along the Aegean Coast of Turkey
(Istanbul Univ Press, Fac Aquatic Sciences, 2019) Mete, Akile Esenliogullari; Tosunoglu, Zafer
In this study, the interactions (encountering and bycatching) of the sea turtles with fisheries in the Aegean Sea were investigated. Data were collected by face-to-face survey with a total of 404 fishermen in 98 fisheries cooperatives for 5 provinces (Canakkale, Balikesir, Izmir, Aydin and Mugla) between August 2016 and October 2017. The interactions are more intense in places where fishing activities coincide with the living areas of these living beings. Although there is maximum (100%) interaction (visual contact) on the coast of Aydin (100%), the average annual encounter within these five provinces is quite high with 88%. While there is a significant difference in the rate of encounters with turtles had been found between the provinces (p< 0.05), there is no significant difference in the rate of bycatching with fishing gears (p> 0.05). Even though one of every four fishermen who participated in the survey had bycaught sea turtles at least once, the most of bycatching occurred in the fishing gears in the group of trammel/gill nets with 76%. In areas where sea turtles are concentrated on the Aegean coast, applications should be carried out to prevent or reduce incidental catch of the fishing gears. Because the results show that these living beings are heading towards the Aegean north due to global
Length-based estimates of growth parameters, mortality rates, and recruitment of Astacus leptodactylus (Eschscholtz, 1823) (Decapoda, Astacidae) in unexploited inland waters of the northern Marmara region, European Turkey)
(Brill Academic Publishers, 2007) Deval, Mehmet C.; Boek, Tomris; Ates, Celal; Tosunoglu, Zafer
The growth parameters, mortality rates, and recruitment pattern of Astacus leptodactylus from an unexploited area in inland waters of the northern Marmara region were investigated based on length-frequency data using FISAT software. Specimens were collected during eight scientific samplings carried out between March 2005 and May 2006. The seasonalized Von Bertalanffy growth function was fitted to the length frequency data (n = 2434) with the following parameters: L-infinity = 80.8 mm, K = 0.405 year(-1), C = 1, and WP = 0.90. The study of functional regressions permits us to conclude that the growth of this population is allometric. Natural mortality (M) was estimated at 0.578 year(-1)and total mortality at 0.589 year(-1). The longevity of the crayfish was calculated as t (max) = 7.4 year. The recruitment pattern shows that there is peak recruitment in May and June. We also estimated the potential instantaneous fishing mortality coefficient at F = 1.53-1.63 year(-1), the instantaneous total mortality coefficient at Z = 2.11-2.21 year(-1), and the exploitation rate E = 0.72-0.73, all through the length-converted catch curve procedure using the length-frequency data of the fyke-nets of 32 mm polyamide (PA) mesh size (stretched mesh).
Management paradox of groupers (Epinephelinae) fishing in the Gokova Bay (Eastern Mediterranean), Turkey
(Wfl Publ, 2009) Unal, Vahdet; Erdem, Mustafa; Goncuoglu, Huriye; Guclusoy, Harun; Tosunoglu, Zafer
The present study attempts to find out the paradox in management of grouper fishing in southern Aegean Sea, Turkey. The study also proposes some Suggestions for a more rational and more effective management of this species. Material of the study is composed of records of fishing cooperatives in the area, interview with the cooperative managers, annual grouper length values and catch-effort data. Throughout the season, 2411 fishing operations have been carried, 383 of which have been focused on especially groupers. The total catch has been recorded as 1448 kg, with a CPUE value of 3.78 kg per vessel. The study also reveals that the ratio of groupers caught below legally allowed length is 13.3%, however, considering outputs of the studies made on the biology of the species, it has also been observed that 85% of the sampled groupers in Gokova bay are prematurely caught before they reach the sexual maturity required for guaranteed sustainability, and thus the species is endangered. Hence, it is very essential to determine the reproductive cycle of groupers, which are the most important species in the fishery of Gokova Bay. However, species selectivity is impossible with the currently used gears. Therefore it would be more rational and effective to determine the reproduction areas of the related species and declare these areas "No Take Zones" which is going to affect postively not only the species but also whole ecoystem they live in.
Morphometric relationships of length-length and length-weight in Parapenaeus longirostris (Lucas, 1846) (Decapoda, Penaeidae)
(Brill Academic Publishers, 2007) Tosunoglu, Zafer; Ozaydin, Okan; Deval, Mehmet C.
The objective of this study was to determine the length-length and length-weight relationships in Parapenaeus longirostris as a basis for conversions. Specimens were collected with hauls from the commercial trawler "Hapuloglu" between 9 and 12 December 2006 in Sigacik Bay and Kusadasi Bay in the Aegean Sea. Morphometric equations for the conversions of length and weight were constructed for females, males, and combined sexes. The equations for carapace length (CL), total length (TL), and body width (BW) for combined sexes were found as CL = 0.2296 x TL - 2.272, r(2) = 0.97, BW = 0.3708 x CL + 0.7694, r(2) = 0.91, and BW = 0.0861 x TL - 0.169, r(2) = 0.90, respectively. The length-weight relationship was determined as W = 0.0031 x TL3.108, r(2) = 0.98 for total length and W = 0.546 x CL2.743, r(2) = 0.97 for carapace length. Males were generally smaller than females (K-S test; p < 0.05) and size-frequency distributions (TL, CL, and BW) revealed differences between females and males (K-S test; p < 0.05). Various length-length and length-weight regressions were also found to differ with sex (F test; p < 0.05), except TL-CL (F = 0.40; p > 0.05).

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