Iglesias, M. (Magdalena)

Rodríguez-Castañeda, J.C.

Ventero, A. (Ana)

English

Rodríguez-Castañeda, J.C. (José Carlos)

Repositorio Institucional Digital del IEO

Interannual analysis of the biological parameters of Trachurusmediterraneus (Steindachner 1868) in the Spanish Mediterranean SeaJosé Carlos Rodríguez-Castañeda, Ana Ventero and Magdalena IglesiasStudies• Semi-pelagic and oceanodrome• Between 40 and 200 m depth• Muddy and sandy bottoms• Mediterranean, Marmara andBlack SeasDistribution• ¿Adriatic Sea?• ¿Marmara Sea?• ¿Black Sea?• ¿Spanish Mediterranean Sea?Biology• Spawning: spring and summer• Maximum size of 40-60 cm• Lifespan: 10 and 12 years• Feeding on larvae andcrustaceansINTRODUCTIONTrachurus mediterraneus (Steindachner 1868) Carangidae family, important fishery resource in the Mediterranean Sea(Smith-Vaniz et al. 1986; Fischer et al. 1987; Relini et al. 1999; Ragonese et al. 2002; Turan 2004; Fernandez-Jover et al. 2007; Mir-Arguimbau et al. 2019)L-WStock assessment-Biomass estimation-Fish condition-CFPhysiological state-Reproduction-Feeding processes-LFD-Recruitment-Growth  -MortalityL50-Length at first maturity-Minimum catch sizeConsidering the scarcity of information regarding the biological parameters and population structure of T. mediterraneus in the Spanish Mediterranean, the present research aims to analyze the temporal evolution of the biological parameters of this species.Petrakis and Stergiou 1995; Gonçalves et al. 1997; Richter et al. 2000; Froese 2006; Neumann y Allen 2007; Hashiguti et al. 2018INTRODUCTIONMATERIALS AND METHODSFigure 1. Geographical location of the study area located in the Spanish Mediterranean Sea.Study area GSA06GSA01From 30 to 200 m depthTransects8 nautical miles 4 nautical milesGSA01GSA06Pelagic trawlsfrom 2016 to 2020 (June-July)MATERIALS AND METHODSSamplingStep 1Total length Wet weight Sex Maturity  Pelagic trawls Separation by species Group of 0.5 cm Step 2 Step 3 Step 4MATERIALS AND METHODSStatisticsLength frequency distribution (LFD) Bhattacharya method Kolmogorov-Sminov (K-S) test (Neumann and Allen 2007)Length-weight relationship (L-W) 𝑾𝒊 = 𝛂𝑳𝒊𝜷𝒆∈𝒊 𝟏Two-way analysis of variance β≠3  t-Student testCondition factor (CF) 𝑲 =𝑾𝒊𝑳𝒊𝜷𝒊∗ 𝟏𝟎𝟎 𝟐 Analysis of covariance𝝌𝟐 =෍𝒐𝒊 − 𝒆𝒊𝟐𝒆𝒊𝟑Sex ratioSize at first maturity (L50) 𝒑 =𝟏𝟎𝟎𝟏 + 𝒆 𝜶+𝜷 ∗𝑳𝟒(Zar 1996)Generalized linear modelChi-square contrast testTukey RESULTSLength frequency distribution (LFD)Figure 2. Annual size structure of horse mackerel T. mediterraneus by zones (GSA06 and GSA01). a) Frequency of standardized sizes and b) Frequency of non-standardized sizes. From 4 to 42.5 cm in total length- Two, three or four modal classesFirst year class (age 0)GSA01 2017GSA06 2016Significant differences between GSA (p<0.05)GSA01    >    GSA06a) b)RESULTSLength-weight relationship Figure 3. General potential relationship between length and average weight.FemalesGSA01 Negative allometric growth GSA06 Males WeightLengthGSA01 GSA06 2016  - 2017  - 2018  - 2019  - 20202016  - 2017  - 2018  - 2019  - 2020IsometricAnnualRESULTSCondition factor (CF)Figure 4. Annual global variation of the condition factor of Trachurus mediterraneus in the Spanish Mediterranean.(2017) K=0.84 ± 0.06Years (p<0.0001)GlobalK=1.12 ± 0.17 K=0.94 ± 0.08Sexes (p<0.0001) K=1.06 ± 0.13 K=0.86 ± 0.13(p<0.0001) (2016) K= 1.02 ± 0.07GSA06GSA01Males Females Global GSA06GSA01RESULTSSex ratioGLOBAL GSA06 GSA01Year F:M χ2 P-value F:M χ2 P-value F:M χ2 P-value2016 0,95:1 0,21 0,646* 1,88:1 16,24 <0,0001 0,65:1 13,85 0,00022017 0,76:1 8,43 0,0036 0,75:1 7,51 0,0061 0,82:1 1,09 0,2965*2018 0,72:1 19,13 <0,0001 0,83:1 3,45 0,0631* 0,60:1 19,50 <0,00012019 0,65:1 35,22 <0,0001 0,63:1 23,31 <0,0001 0,67:1 31,00 <0,00012020 0,65:1 39,58 <0,0001 0,64:1 32,00 <0,0001 0,63:1 11,97 0,0005Table 1. Variation of the sexual proportion of T. mediterraneus during the study period and areas. M: Males; F: Females1M:0.72F (χ2 = 92.01; p<0.001)Relationships were similar during the study period and areasException GSA06 in 2016 1:1GeneralGlobal in 2016 - GSA06 in 2018 – GSA01 in 2017:::1M:1.88FAño GLOBAL (cm) D2 (%) GSA06 (cm) D2 (%) GSA01 (cm) D2 (%) 2016 15,77 69,9 15,09 75,7 16,00 78,7 2017 15,14 77,7 15,82 80,5 16,40 85,3 2018 13,57 30,8 13,81 33,3 15,51 60,2 2019 14,53 61,9 14,70 62,9 15,71 83,5 2020 13,11 28,8 13,17 38,7 12,16 11,9  RESULTSSize at first maturity (L50)Figure 9. Logistic model of the first size of sexual maturity (L50)Global GSA06GSA01Table 2. Periodic variation of the first sexual maturity size (L50)L50 14,11 cm (D2 =58%) Global L50  14,4 (D2=49%)L50  15,34 cm (D2=61%)GSA01GSA0614 - 42,5 cm 12,8 - 37 cm 19,6 cm 19,2 cm13,2 - 39,5 cm 12,6 - 39,2 cmMature intervalFemales Males Immature maximunYear(p<0.05)DISCUSSIONMelnikova (2019) and Kutsyn (2021)From 6 to 22 cm in standard lengthRagonese et al. (2002)• Three modal classes and a possible fourth• Juvenile recruits of 8 cm• Meta-populations from different localities• R-type strategistsCuscó (2015)• Engraulis encrasicolus• Larger populations of age 0 and 1 in GSA01 compared to GSA06 • Higher primary production and chlorophyll in GSA01• Favorable environmental conditionsLFDVentero et al. (2017)GSA01         >         GSA06DISCUSSIONL-W• β coefficient differsAk et al. (2009), Satılmış et al. (2014),Özdemir et al. (2015) and Melnikova (2019)• Positive allometric growthProdanov et al. (1997) and Yankovaet al. (2010)Tzikas et al. (2007)Observed differences could be due to sampling procedure, sample size, length range or environmental factors.• Negative allometric growthReported β values between 2.9 and 3, suggesting variations in growth over the months and yearsTime of the yearHabitatDegree of stomach fullnessMaturation of gonadsHealth and general condition of the fishReason(Froese 2006; Yankova et al. 2010)DISCUSSIONCFŠantić et al. (2011)• Status lower for males and females• K<1General nutritional stateConsequently, variations between zones may be influenced by the effects of coastal upwelling in the region, adverse conditions or food availability (Ambriz-Arreola et al. 2012)Females invest substantially more energy inreproductive development than males(King 1995)Various authors use the value 3 as the power in the equation for calculating the condition factor, making comparisons difficultCuscó (2015)Age SexSeason FoodReserves Muscle(Barnham and Baxter 1998)GSA01     >     GSA06Male >      FemaleDISCUSSIONSex ratioMelnikova (2019)• Males generally dominant over femalesMeléndez-Vallejo et al. (2017)and Yankova et al. (2010a)• Females dominated over malesCarrillo (1978), Raykov and Yankova(2005), Yankova et al. (2010b) andKutsyn (2021)• Obtained a 1:1 ratioThe sex ratio tends to be 1:1 between males and females• Varies from year to year within the same population• Reproduction periodThe sampling time coincides with the reproduction of the speciesVariation in the proportion of females and males may be due to physiological factors during spawning. Furthermore, in some cases males may be more vulnerable to the art than femalesDISCUSSIONL50Samia et al. (2002)• Northern Tunisia, Africa, with 15.7 cmDemirel and Yuksek (2013)• Mamara Sea 12.2 and 12.5 cmAk et al. (2015)• Black Sea 11.52 and 11.97 cm • Stock difference• Fishing pressure • Phylogenetic, morphological and genetic characteristics (Turan 2004; Bektas and Belduz 2008)L50 14.11 cmGlobal GSA01 GSA0616.40 cmThe model is determined by the set of mature and immature individuals analyzed during the study• Proposal of Ventero et al. (2017)Using the sizes of the models that managed to explain the greater variabilityGSA01 GSA0615.82 cm(Leal et al. 2013)CONCLUSIONS• The LFDs showed significant differences in length according to age, suggesting that T. mediterraneuspresents a greater length in GSA01 compared to GSA06, possibly favored by a greater availability of food.• T. mediterraneus showed negative allometric growth with some isometric type oscillations in GSA06 due toits condition status.• T. mediterraneus presented a better condition status in GSA01 than in GSA06. In addition, in this area themales presented a better condition than the females, which invest their energy in spawning.• The sex ratio did not respond to the expected 1: 1. Males predominated over females, probably due tophysiological factors during reproduction.• The selection of the L50 was based on the most precise model, in which significant differences weredetected between the GSAs, suggesting the use of 16.40 cm in GSA01 and 15.82 cm in GS06 as sizes at firstmaturity to establish sizes at first catch as part of the future management of this resource in theMediterranean Sea.Thank you for your attentionThank Balearic Oceanographic Centre (COB)

Interannual analysis of the biological parameters of Trachurus mediterraneus (Steindachner 1868) in the Spanish Mediterranean Sea

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