A General Linear Modeling (GLM)approach to analysis of variance was used to
analyze swordfish logged catch rates in number of fish from
24
,
239
trips carried out by
the Spanish surface longline fleet addressed to this species in the Western
Mediterranean f
or the period 1988
-
2013.Postprin

Macías-López, A.D. (Ángel David)

Mejuto-García, J. (Jaime)

Ortiz-de-Urbina-Gutiérrez, J.M. (José María)

Saber-Rodríguez, S. (Sámar)

Serna-Ernst, J.M. (José Miguel) de-la

English

A General Linear Modeling (GLM)approach to analysis of variance was used to
analyze swordfish logged catch rates in number of fish from
24
,
239
trips carried out by
the Spanish surface longline fleet addressed to this species in the Western
Mediterranean f
or the period 1988
-
2013

Saber, S. (Sámar)

Repositorio Institucional Digital del IEO

SCRS/2014/096 UPDATED STANDARDIZED CATCH RATES IN NUMBER FOR SWORDFISH (Xiphias gladius L.) CAUGHT BY THE SPANISH LONGLINE FLEET IN THE MEDITERRANEAN SEA, 1988- 2013.  J. Ortiz de Urbina1, J. M. de la Serna1, J. Mejuto2, D. Macías1, S. Saber1  SUMMARY  A General Linear Modeling (GLM) approach to analysis of variance was used to analyze swordfish logged catch rates in number of fish from 24,239 trips carried out by the Spanish surface longline fleet addressed to this species in the Western Mediterranean for the period 1988 -2013.  RESUMEN  Mediante técnicas de Modelado Lineal Generalizado (GLM), se analizaron las tasas de captura de pez espada en número de peces, transformadas mediante aplicación de logaritmos naturales, procedentes de 24.239 mareas de la flota española de palangre de superficie dirigido a esta especie en el Mediterráneo Occidental desde 1988 a 2013.  KEYWORDS  Catch/effort, Least squares method, Abundance, Long lining, Swordfish.                      1 Instituto Español de Oceanografía, C. O. Málaga (Fuengirola). Puerto Pesquero s/n. Apdo.: 285. 29640 Fuengirola (Málaga). Spain. E-mail: urbina@ma.ieo.es. 2 Instituto Español de Oceanografía, C. O. A Coruña  SCRS/2014/096 1. MATERIAL AND METHODS 1.1. Basic data. Data for the analysis were obtained from the Spanish longline activity in the Mediterranean Sea targeting swordfish from 1988 to 2013. As in previous analyses (Mejuto & de la Serna, 1995; Ortiz de Urbina & de la Serna, 1999; Ortiz de Urbina et al, 2004, Ortiz de Urbina et al, 2007; Ortiz de Urbina et al, 2011), information of catch by vessel/trip- including date, area of the catch, catch in number and fishing effort- was recorded by the Information and Sampling Network of the Spanish Institute of Oceanography (IEO) at the most important landing ports for the aforementioned fleet. A comprehensive description of the Spanish longline fishery directed to swordfish in the Mediterranean Sea was previously presented by de la Serna et al (2004).  Raw data for positive trips (trips with at least one fish) were estructured as follows: vessel code, date of landing, landing in number of fish, number of sampled fish, catch by LJFL (5 cm interval), quadrant, area (5 x 5 degrees), number of sets, hooks by set and type of bait. A total of 24, 239 records were available for the analyses.  Following traditional criteria, nominal effort by trip was defined as number of hooks (in thousands of hooks) computed from the number of sets carried out during the trip and the mean number of hooks by set.  1.2. Model and Specifications. Three previosly defined areas (Mejuto & de la Serna, 1994) were used in the analyses. As regards temporal definition, it corresponded to the following quarters:  Quarter 1: January, February, March Quarter 2: April, May, June Quarter 3: July, August, September Quarter 4: October, November, December  The basic multiplicative model (Gavaris, 1980; 1988) was defined as follows:  Ln (CPUE) = μ + Yi + Qj + Ak + Qj*Ak + eijk  μ = overall mean Yi = effect year i Qj = effect quarter j Ak = effect area k eijk = normal error  2. RESULTS AND DISCUSSION. Table 1 shows the number of observations per year/area/quarter in the analyses. A total of 24,239 positive trips were used in the analyses. In general, the number of observations by cell may be considered satisfactory.  SCRS/2014/096 The deviance analysis results for catch rates standardization are shown in Table 2. Final model for catch rates in number of fish included factors Quarter and Area as well as the corresponding interaction Quarter*Area (all factors statistically significant at the 1% level, except the Quarter*Area interaction for model with catch rates in number of fish). The variability rate explained by the model was about 14 %.  Diagnostic plots (residuals vs. fitted values and cumulative normalized residual plots) for CPUE in number, shown in Figure 1, seem to be not far from expected. Annual relative abundance indices with corresponding 95% upper and lower confidence limits (Table 3 and Figure 2) were obtained from the marginal means adjusted for the GLM statistically significant terms.  3. LITERATURE CITED de la Serna, J.M, D. Macías, J.Mª Ortiz de Urbina, E.Alot, P.Rioja. 2004. Análisis de la pesquería española de pez espada (Xiphias gladius) en el Mediterráneo.  864-871 ICCAT Col. Vol. Sci. Pap. Vol LVI(3): 864- 871.  Gavaris, S. 1980. Use of multiplicative model to estimate catch rate and effort from commercial data. Can. J. Fish. Aquat. Sci. 37:2272- 2275.  Gavaris, S. 1988. Abundance indices from commercial fishing. Collected papers on stock assessment methods. CAFSAC Res. Doc. 88/61. 167 pp.  Mejuto, J. and J. M. de la Serna. 1995. Standardized catch rates in number and weight for the swordfish (Xiphias gladius L.) from the Spanish longline fleet in the Mediterranean Sea, 1988- 1993. ICCAT Col. Vol. Sci. Pap. Vol XLIV(I): 124- 129.  Ortiz de Urbina, J. Mª and J. M. de la Serna. 1999. Updated standardized catch rates in number and weight for the swordfish (Xiphias gladius L.) from the Spanish longline fleet in the Mediterranean Sea, 1988- 1997. ICCAT Col. Vol. Sci. Pap. Vol XLIX(I): 105- 109.  Ortiz de Urbina, J.Mª, J.M. de la Serna, J. Mejuto, P.Rioja, D. Macías. 2004. Updated standardized catch rates in number and weight for the swordfish (Xiphias gladius L.) from the Spanish longline fleet in the Mediterranean Sea, 1988- 2001. ICCAT Col. Vol. Sci. Pap. Vol LVI(3): 872- 880.  Ortiz de Urbina, J.Mª, J.M. de la Serna, J. Mejuto, P.Rioja, D. Macías. 2008. Updated standardized catch rates in number and weight for the swordfish (Xiphias gladius L.) from the Spanish longline fleet in the Mediterranean Sea, 1988- 2001. ICCAT Col. Vol. Sci. Pap. Vol LXII(4): 1122- 1127.  Ortiz de Urbina, J.Mª, J.M. de la Serna, J. Mejuto, P.Rioja, D. Macías. 2011. Updated standardized catch rates in number and weight for the swordfish (Xiphias gladius L.) from the Spanish longline fleet in the Mediterranean Sea, 1988- 2009. ICCAT Col. Vol. Sci. Pap. Vol LXVI(4): 1515- 1521.    SCRS/2014/096 Table 1. Number of observations by year/quarter/area for the Spanish longline fishery in the Western Mediterranean.   Quarter 1 Quarter 2 Quarter 3 Quarter 4 year Area 2 Area 3 Area 5 Area 2 Area 3 Area 5 Area 2 Area 3 Area 5 Area 2 Area 3 Area 5 1988 1 33 4 43 60 28 80 69 177 49 49 18 1989 37 38 5 140 77 2 223 100 162 114 43 27 1990 47 27 0 117 54 12 224 150 285 115 71 69 1991 35 44 2 108 75 0 162 101 146 115 74 0 1992 21 55 0 80 54 10 358 187 95 130 147 17 1993 163 51 5 218 38 19 541 85 74 254 85 18 1994 196 56 0 195 54 7 596 169 136 327 129 32 1995 124 60 39 234 39 2 563 202 93 340 180 108 1996 158 73 13 149 27 0 382 208 100 197 140 46 1997 81 48 4 110 12 0 427 65 72 219 18 55 1998 96 8 21 122 40 0 281 84 71 170 59 44 1999 59 32 13 54 4 23 177 70 35 97 78 54 2000 53 6 25 37 16 0 97 148 44 80 68 27 2001 88 16 0 104 17 0 199 217 0 191 105 0 2002 160 10 2 112 11 0 280 299 2 205 89 2 2003 80 13 0 89 56 0 93 233 0 94 131 0 2004 35 23 0 12 11 0 87 161 4 65 94 44 2005 16 21 0 10 0 0 41 93 8 27 71 18 2006 9 2 0 8 0 0 58 46 4 40 56 17 2007 14 7 7 9 4 4 13 31 38 14 18 59 2008 0 17 10 5 8 25 96 65 69 29 61 19 2009 2 25 17 13 23 50 298 155 117 46 11 20 2010 35 20 43 20 7 27 286 89 155 17 20 34 2011 32 26 36 31 9 33 376 103 106 28 7 46 2012 25 33 44 1 36 17 158 91 54 27 6 1 2013 68 125 71 29 121 58 611 266 134 89 53 62    Table 2. Deviance analysis of explanatory factors in the lognormal model for swordfish catch rates in number of fish from the Spanish longline fishery in the Western Mediterranean.     residual change in % of total model %  Model factors (lnCPUEn) df deviance deviance deviance deviance p-value NULL 24238 14323     Year 24213 13422 900.83 6.29 6.29 2.20E-16 Year Quarter 24210 12471 950.90 6.64 12.93 2.20E-16 Year Quarter Area 24208 12455 16.71 0.12 13.05 8.27E-08 Year Quarter Area Quarter*Area 24202 12388 66.56 0.46 13.51 2.20E-16          SCRS/2014/096 Table 3. GLM least squares means by year, standard error, coefficient of variation, relative abundance indices by year and corresponding upper and lower 95% confidence limits based on a normal approximation. Catch rates in number of fish. Spanish longline fishery in the Western Mediterranean.    lsmean       lnCPUEn std. Error CV(%) CPUEn upper 95% lower 95% 1988 2.282 0.035 1.518 9.800 10.489 9.157 1989 1.849 0.029 1.578 6.353 6.727 6.000 1990 2.072 0.028 1.333 7.943 8.385 7.525 1991 1.749 0.030 1.731 5.746 6.097 5.415 1992 1.824 0.028 1.527 6.196 6.543 5.866 1993 1.835 0.025 1.343 6.264 6.574 5.969 1994 1.935 0.023 1.208 6.922 7.247 6.612 1995 1.916 0.024 1.236 6.792 7.114 6.484 1996 1.659 0.025 1.498 5.253 5.515 5.003 1997 1.628 0.028 1.693 5.096 5.379 4.828 1998 1.800 0.028 1.566 6.052 6.396 5.727 1999 1.605 0.032 1.996 4.979 5.302 4.676 2000 1.619 0.034 2.087 5.046 5.392 4.723 2001 1.605 0.029 1.798 4.977 5.266 4.703 2002 2.171 0.026 1.216 8.768 9.234 8.326 2003 1.647 0.031 1.859 5.190 5.510 4.887 2004 1.413 0.036 2.519 4.108 4.404 3.831 2005 1.613 0.045 2.773 5.020 5.480 4.599 2006 1.765 0.050 2.811 5.842 6.439 5.301 2007 2.037 0.052 2.548 7.668 8.489 6.926 2008 2.078 0.040 1.939 7.986 8.642 7.379 2009 1.464 0.032 2.174 4.324 4.602 4.062 2010 1.591 0.032 1.995 4.909 5.224 4.613 2011 1.711 0.031 1.796 5.535 5.878 5.211 2012 1.897 0.037 1.948 6.669 7.170 6.203 2013 1.641 0.025 1.528 5.162 5.422 4.914                     SCRS/2014/096     Figure 1. Diagnostic plots: residuals vs. fitted values (left) and cumulative normalized residual plot (right) for the lognormal model fit to swordfish catch rates (number of fish).    SCRS/2014/096   Figure 2. Standardized CPUE index, corresponding 95% confidence limits (normal approximation) and trend (LOESS fit). Number of fish. Spanish longline fishery in the Western Mediterranean.  

UPDATED STANDARDIZED CATCH RATES IN NUMBER FOR SWORDFISH (Xiphias gladius L.) CAUGHT BY THE SPANISH LONGLINE FLEET IN THE MEDITERRANEAN SEA, 1988- 2013

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UPDATED STANDARDIZED CATCH RATES IN NUMBER FOR SWORDFISH (Xiphias gladius L.) CAUGHT BY THE SPANISH LONGLINE FLEET IN THE MEDITERRANEAN SEA, 1988- 2013

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