Parapenaeus longirostris (Lucas, 1846) is one of the most economically important decapod species in the trawl fishery on the Montenegrin shelf (southern Adriatic Sea). Despite its importance, there were no biological studies on the species for that area. Data were obtained from monthly samples taken from commercial catches realized in the southern Adriatic during the period from November 2006 to October 2007 and from June 2009 to May 2010. During the first year among the 1979 specimens, 71.80% were females and 28.20% males, while during the second year of investigation, among the 1967 specimens, 66.30% were females and 33.70% males. The overall sex ratio was in favour of females. The carapace length of all specimens ranged from 15 to 37 mm, with a mean of 25.23 ± 4.48, while during the second year the range of carapace length of all specimens was wider and ranged from 11 to 37 mm, with a mean of 24.85 ± 4.48. A marked sexual dimorphism was observed between males and females: females have a wider size range, greater size and weight. Percentage of females reached 100% in the 28-30 mm size class and beyond. Males were in better condition than females. The calculated allometric coefficient of length-weight relationships was b= 2.58 for the total sample of 2006-2007 year, b= 2.51 for females and b= 2.34 for males; while during the 2009-2010 values were b=2.59 for the total sample, b=2.57 for females and b=2.33 for males. The size at which 50% of the female population reached maturity was at a carapace length of 20.48 mm in the first year and 19.89 mm during the second year. An estimate of the gonadosomatic index (GSI) showed permanent reproductive activity all year round In the first year of investigation, the estimated growth parameters were L∞ = 42.86 mm, K = 0.49, t0 = -0.37 for the total sample; L∞ = 43.93 mm, K = 0.42, t0 = -0.62 for females and L∞ = 30.94 mm, K = 0.49, t0 = -0.13 for males. In the second year, values of these parameters were L∞ = 43.93 mm, K = 0.55, t0 = -0.672 for the total sample; L∞ = 42.07 mm, K = 0.61, t0 = -0.643 for females and for males L∞ = 33.93 mm, K = 0.49, t0 = -0.165. Asymptotes of weight growth function were W∞= 30.91 g for females, W∞= 11.25 g for males and for the all specimens together W∞= 24.10 g, while for the 2009-2010 these values were W∞= 28.50 g for females, W∞= 14.00 g for males and W∞= 30.77 g for the all specimens together. Growth performance index was in favour of females. The calculated mean values of total mortality coefficient (Z) for the 2006-2007 period were Zf+m.= 1.60, Zf = 1.44, Zm= 1.24, and for the 2009-2010 period these values were Zf+m= 1.92, Zf = 1.74, Zm=1.57, while the values of natural mortality coefficient (M) were Mf+m= 0.76, Mf = 0.67, Mm= 0.80 for the first period, and Mf+m= 0.85, Mf = 0.93, Mm= 0.78 for the second period.The size at first capture was L50% = 27.26 mm (t50%=1.72 year) in the 2006-2007 period, and L50% = 25.63 mm (t50%=0.96 year) in the 2009-2010 period. As the minimum carapace length at which this species reaches maturity is about 20 mm, use of 20 mm cod-end mesh size does not pose a threat to population renewal so far. The F values obtained in males and females were 0.44 and 0.77, respectively and 0.84 for the total 2006-2007 sample. For the 2009-2010 sample F value was 1.07, and for males and females were 0.79 and 0.81, respectively. During the both years, the value of the current exploitation rate was below the predicted maximum value 0.52<0.958 during the first and 0.56<0.845 during the second year.As the value of fishing mortality was higher than on natural mortality (F>M) and value of E>0.5, we may conclude that the stock of Parapenaeus longirostris on the shelf of Montenegrin coast is under intense fishing pressure and is overexploited. Jedna od najvažnijih komercijalnih vrsta dekapodnih rakova u kočarskom ribolovu na šelfu Crnogorskog primorja je kozica, Parapenaeus longirostris (Lucas, 1846). Istraživanje je obavljeno tokom dvije godine, od novembra 2006. do oktobra 2007. i od juna 2009. do maja 2010. godine pri čemu su uzorci uzimani sa kočarskih brodova mjesečnom dinamikom. Tokom prve godine je ukupno obrađeno 1979 jedinki, od kojih su 1421 (71.80%) bile ženke a 558 (28.20%) mužjaci. Odnos polova je i u drugoj godini bio u korist ženki tokom koje je analizirano 1967 jedinki, od kojih su 1304 (66.30%) bile ženke a 663 (33.70%) mužjaci. Raspon dužina karapaksa svih ulovljenih jedinki zajedno je bio manji u prvoj godini i kretao se od 15 do 37 mm (25.23 ± 4.48) dok je u drugoj taj raspon bio 11-37 mm (24.85 ± 4.48). Uočen je polni dimorfizam: ženke su u prosjeku i duže i teže od mužjaka, i u dužinskim grupama >28- 30 mm CL su 100% prisutne u ulovu. Mužjaci su u boljoj kondiciji od ženki. Vrijednosti alometrijskog koeficijenata b dužinsko-težinskog odnosa u prvoj godini iznose b = 2.58 za ukupan uzorak, b = 2.51 za ženke i b = 2.34 za mužjake; dok te vrijednosti za drugu godinu iznose b = 2.59 za ukupan uzorak, b = 2.57 za ženke i b = 2.33 za mužjake. Prva polna zrelost ženki je nastupila pri dužini karapaksa od 20.48 mm u prvoj godini, odnosno od 19.89 mm CL u drugoj godini. Kozice se mrijesti tokom cijele godine, zabilježena su dva maksimuma reproduktivne aktivnosti: u proljeće i u jesen. U prvoj godini, procijenjeni parametri rasta su L∞ = 42.86 mm, K = 0.49 i t0 = - 0.37 za ukupan uzorak; L∞ = 43.93 mm, K = 0.42 i t0 = -0.62 za ženke i L∞ = 30.94 mm, K = 0.49 i t0 = -0.13 za mužjake. U drugoj godini, parametri rasta ukupnog uzorka iznose L∞ = 43.93 mm, K = 0.55 i t0 = -0.672; ženki L∞ = 42.07 mm, K = 0.61 i t0 = - 0.643 i mužjaka L∞ = 33.93 mm, K = 0.49 i t0 = -0.165. Asimptote težinskog rasta u funkciji vremena u prvoj godini bile su za ženke W∞ = 30.91 g, za mužjake W∞ = 11.25 g i W∞ = 24.10 g za ukupan uzorak, dok su te vrijednosti u drugoj godini za ženke W∞ = 28.50 g, za mužjake W∞ = 14.00 g i za ukupan uzorak W∞ = 30.77 g. Procijenjena srednja vrijednost stope ukupne trenutne smrtnosti u 2006-2007 godini iznosi Zž+m= 1.60, Zž = 1.44, Zm= 1.24, a za 2009-2010 Zž+m= 1.92, Zž = 1.74, Zm=1.57, dok je srednja vrijednost stope prirodne smrtnosti u prvoj godini bila Mž+m= 0.76, Mž = 0.67, Mm= 0.80, a u drugoj Mž+m= 0.85, Mž = 0.93, Mm= 0.78. Dužina 50% zadržavanja jedinki u mreži je L50% = 27.26 mm, što prevedeno u vremensku skalu odgovara starosti t50% = 1.72 godine tokom 2006-2007. U 2009-2010 L50% je iznosila 25.63 mm, što odgovara starosti t50% = 0.96 godina. S obzirom da je minimalna dužina karapaksa pri kojoj ova vrsta dostiže polnu zrelost oko 20 mm, upotreba oka od 20 mm za sada bitno ne ugrožava obnavljanje populacije ove vrste. Na osnovu vrijednosti Z i M izračunata je stopa ribolovne smrtnosti F koja je u 2006-2007 imala vrijednost Fž+m= 0.84, Fž = 0.77, Fm= 0.44, a u 2009-2010 Fž+m= 1.07, Fž = 0.81, Fm= 0.79. Tokom obje godine stvarna stopa eksploatacije je bila manja od maksimalne stope eksploatacije tj. 0.52<0.958 tokom prve i 0.56<0.845 tokom druge godine. Ovim istraživanjem, s obzirom da je vrijednost stope ribolovne smrtnosti F>M i da je E>0.5, možemo zaključiti da je stok kozice u južnom Jadranu prelovljen.