Díaz-Conde, M.P. (María Paz)

González-Cabrera, C. (Carmen)

Jiménez, M.P. (María Paz)

Martínez, M. ()

Ramos, F. (Fernando)

Tornero, J. (Jorge)

English

Jiménez, María Paz

Ramos, Fernando

Díaz-Conde, María Paz

Tornero, Jorge

González-Cabrera, Carmen

Martínez,

Digital.CSIC

Anchovy Spawning Stock Biomass of the Gulf of Cadiz in 2020 by the DEPM

Repositorio Institucional Digital del IEO

Anchovy Spawning Stock Biomass of the Gulf of Cadiz in 2020   by the DEPM   By  MP. Jiménez, F. Ramos, P. Díaz, J. Tornero, C. González and M. Martínez   CENTRO NACIONAL INSTITUTO ESPAÑOL DE OCEANOGRAFÍA CENTRO OCEANOGRÁFICO DE CÁDIZ  ICES Working Group on Acoustic and Egg Surveys for small pelagic fish in  NE Atlantic. Online meeting, 15 - 19 November 2021  General sampling information Eggs Anchovy DEPM survey BOCADEVA 0720 Survey area (36º13’-36º50’N –6º07’-–8º55’W ) R/V R/V Ramón Margalef Date 9th to 17th  July 2020 Transects (Sampling grid) 21 (8x3) Pairovet stations (150 μm) 162 Sampling maximum depth (m) 100 Hydrographic  sensor CTD SBE 911 Flowmeter Yes CUFES stations 152 CUFES (335 μm) 3 n miles (sample unit) Environmental data Temperature and Salinity Adults Acoustic survey ECOCADIZ 2020-07 Survey area (36º11’-36º47’N –6º12’-–8º54’W ) R/V R/V Miguel Oliver Date 31th July  to 13th August 2020 Gears Pelagic trawl (63.5/51 Tuneado gear) Biological sampling: On fresh material, on board the R/V  Sample size At least 60 individuals randomly picked; up to 120 (adding batches of 10 randomly picked anchovies) if a minimum of 30 mature females were not found for spawning fraction estimation. A minimum of 150 hydrated females for batch fecundity estimation. Fixation 4% Phosphate-buffered Formaldehyde Preservation 4% Phosphate-buffered Formaldehyde PairoVET:    150 μm mesh size net   Fixed stations every 3 nm   Vertical hauls (maximum 100m depth)   Underwater positioning systems HiPAP 500 Kongsber     CTD Sea Bird 911 SST and SSS at 5 m (termosalinometer) METHODOLOGY: EGG SAMPLING CUFES 335 μm mesh size net Depth sampling  up to 5 m from the surface   600 l/min flow approximately   Plankton samples preserved in buffered formaldehyde at 4%  METHODOLOGY: ADULTS SAMPLING Adult Samples:   Total of sampled Anchovies (sex & length & weight): 1691. 686 ovaries were collected (180 hydrated females for batch fecundity estimation). Gonads preserved in 4% Phosphate-buffered formaldehyde. . # hauls: 30 # valid hauls: 29 - 25 for echo-traces identification; - 4  for collecting hydrated females. Trawling time: from  06:58 to 21:19 hrs GMT (4 hauls at night targeting hydrated females).  EGGS DATA PairoVET  Total surveyed area: 16223 km2 Positive area: 10058 km2  (62%)  Total stations: 162 Positive stations: 86 (53%) Total Anchovy eggs: 2916 Max. number: 530 Total density: 33873.9 eggs/m2 Max. density: 6161.6 eggs/m2  A total of 152 stations by CUFES were carried out, 69% positive. A total of 36476 eggs of anchovy were caught, the third highest value in the historical series (2005-2020). By Pairovet 2005 2008 2011 2014 2017 2020 N radials 21 21 21 21 21 21 N stations 119 127 125 151 151 162 N positive stations 46 (39%) 84 (66%) 71 (57%) 70 (46%) 52 (34%) 86 (53%) N total eggs 583 1373 2387 3097 949 2916 N maximum eggs 204 104 191 195 215 530 Total density (egg/m2) 11539 14266 24722 33019 10273 33874 Maximum density 4020 1229 2195 2024 2453 6162 EGGS DATA. HISTORICAL SERIES 2005 2008 2011 2014 2017 2020Total density (egg/m2) 11539 14266 24722 33019 10273 33874Max. number 204 104 191 195 215 53001002003004005006000500010000150002000025000300003500040000Eggs/m2The highest estimates of maximum egg density by station and total egg density as sampled by PairoVET were recorded during the 2020 survey.  98% of Anchovy eggs were classified into 11 stages according to the degree of embryonic development (according to the key proposed by Moser and Ahlstrom, 1985). The most abundant stage was stage II (38.5%). Stage I eggs were mainly caught at 23:25 GMT, coincident to the peak spawning for the species in the area (22:00 GMT ± 2h) and the egg development model (Bernal et al., 2012). P0 (eggs/m2/day) =  523.4 (0.38) z (day-1) =  -1.1124 (0.44)  Ptotal (eggs/day) =  5.264431e+12 (0.38)  EGG PARAMETERS ADULT PARAMETERS W = 16.630 g (0.13) F = 8212 eggs (0.14) R = 0.543 (0.009) S: in progress  SSB = 81466 t (0.43)   PRELIMINARY GULF OF CÁDIZ ANCHOVY SSB 2020 Due to the COVID19 pandemic and the consequent confinement and remote work, the histological processing of the gonad samples needed for the reading of POFs and estimation of S has not been possible to finish it yet. So, the mean value of spawning fraction (S) of the historical series has been used provisionally to estimate the SSB for 2020 (S = 0.241 ). DEPM 2020 (Preliminary estimates) & HISTORICAL SERIES (1) Historical series mean value Year 2005 2008 2011 2014 2017 2020 Eggs  P0 (eggs/m2/day)   138 266 276 314 146 523 Z (day-1)    -0.04  -1.43  -0.29  -0.33  -0,16  -1.11 Ptotal (eggs/day) (x1012)  1.13 2.11 1.87 1.95 0.74 5.26 Surveyed area (km2) 11982 13029 13107 14595 15556 16223 Positive area (km2)  6139 6863 6770 6214 5080 10058 Adults  Female Weight (g)  25.2 / 16.7 23.7 15.2 18.2 16.2 16.6 Batch Fecundity 13820 / 11160 13778 7486 7502 7507 8212 Sex Ratio  0.53 / 0.54 0.53 0.53 0.54 0.53 0.54 Spawning Fraction  0.26 / 0.21 0.218 0.276 0.276  0.243 0.241 (1) SSB  Spawning Biomass (t)  14673 31527 32757 31569 12422 81466 BIOMASS (tons) - HISTORICAL SERIES (*) Spanish waters only 2005 2008 2011 2014 2017 2020 ECOCADIZ       29219 12229 44877 PELAGO 15103 39667 27050 30864 13797 49787 BCDV 14673 31527 32757 31569 12392 81466 0 10000 20000 30000 40000 50000 60000 70000 80000 90000 Anchovy  GoC  Biomass  (tons) Year ECOCADIZ (Acoustic) PELAGO (Acoustic) BOCADEVA (DEPM) 2004 18177     2005 - 15103 14673 2006 36521 24082   2007 28882 39965   2008 - 39667 31527 2009 21580 26834   2010    12339 * 8583   2011 - 27050 32757 2012 -     2013 8487 16655   2014 29219 30864 31569 2015 21305 33100   2016 34184 65345   2017 12229 13797 12392 2018 34908 23473 2019 57700 29876 2020 44877 49787 81466 2021 14065 2005 2008 2011 2014 2017 2020 A+ 6139 6863 6770 6214 5080 10058 P0 (eggs/m2/day)   137,65 266 276 314 146 523 0 100 200 300 400 500 600 0 2000 4000 6000 8000 10000 12000 Km2 BOCADEVA series (eggs/day) (x1012) 2005 2008 2011 2014 2017 2020 Ptotal (eggs/day) (x1012)  1,13 2,11 1,87 1,95 0,74 5,26 0,0 1,0 2,0 3,0 4,0 5,0 6,0 Ptot (eggs/m2 /day) 

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Anchovy Spawning Stock Biomass of the Gulf of Cadiz in 2020 by the DEPM

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