EARLY LIFE HISTORY AND STOCK IDENTITY OF HORSE MACKEREL SPECIES
LMR-PEL-09-09
In Angola: in the past Largest fisheries landing in volume; it Trachurus trecae reached 40% of the total fish catches. Currently < 10% of total catch. High national demand
In Namibia: ~ 60% of Trachurus capensis total catch Objec ves ü Determine the stock identity of Cunene horse mackerel found in northern/central Angola and southern Angola;
ü Determine the stock identity of Cape horse mackerel found in southern Angola and northern Namibia;
ü Identification of the main spawning and nursery areas of the two species of horse mackerel;
ü Recommend on appropriate management strategy for the northern Benguela horse mackerel stocks. Iden fica on of the main spawning and nursery areas of the two species of horse mackerel
Ø Data types available: Ø Biological commercial sampling • High temporal coverage • Daily • Low spatial resolution • 3 ports
Ø Survey data • Low temporal coverage • 1 month/year • High spatial resolution • Whole coast When do they spawn? -Spawning cycle- Sampling and fishing among regions -Luanda
80
70
60
50
40 2007
30 2008 2009 20
Propor on of spwaning females 10
0 Jan Feb Mar Apr May Jun Jul Aug Set Out Nov Dez Axis Title Proportion of macroscopic spawning stage 4 (Spawning) Benguela
60
50
40 Versus time 30 2007 2008 20 2009 10
0 Jan Feb Mar Apr May Jun Jul Agu Set Out Nov Dez Propor on of spawning stage Axis Title
1,2 Proportion of 1 Versus Fish size macroscopic spawning 0,8 stage 4 (Spawning) 0,6 2007 n=298 0,4 2008 n=273
0,2 2009- n=160
% Freq of Spawning females 0 23 26 29 32 35 38 41 Lt(cm) Spa al distribu on – Spawning Evolu on with me (Last 5 years)
Cabinda Cabinda Cabinda Cabinda Cabinda 6 6 6 6 6 - - Rio Congo - Rio Congo Rio Congo - Rio Congo - Rio Congo
NZeto NZeto NZeto NZeto NZeto
Ambriz Ambriz Ambriz Ambriz Ambriz 8 8 8 8 8 - - - - - GIS 2011 Luanda Luanda Luanda Luanda GSI GIS GSI Luanda Pta. 2008 Pta. Pta. Pta. 2007 Palmerinhas Palmerinhas 2009 Palmerinhas GSI Palmerinhas Pta. 2010 Palmerinhas 7 0 0 0 0 7 0 1
1 7 1 1 1 - - - -
- 6
6 6 7 Porto 7 Porto Porto Porto 5 Porto Amboim Amboim Amboim Amboim 5 5 6 6 Amboim Sumbe Sumbe Sumbe Sumbe 4 4 4 5 5 Sumbe 3 2 2 2 2
4 2 1 1 3 1 3 1 - -
4 1 - - Lobito - 2 Lobito Lobito 3 Lobito 2 Lobito 2 Benguela Benguela 3 Benguela Benguela 2 1 Benguela 1 1 2 1 0 0 0 S. Marta 1 0 S. Marta 4 S. Marta 4 4 4
S. Marta 4 1 1 1 S. Marta 1 - - - 1 -
0 -
Namibe Namibe Namibe Namibe Namibe 6 6 Tombwa Tombwa 6 Tombwa 6
Tombwa 6 1 1 1 Tombwa 1 - - - 1 - -
Baia dos Tigres Baia dos Tigres Baia dos Tigres Baia dos Tigres Baia dos Tigres Rio Cunene Rio Cunene Rio Cunene Rio Cunene Rio Cunene 8 8 8 8 8 1 1 1 - - 1 - 1 - 10 12 14 10 12 14 10 12 14 - 10 12 14 10 12 14
Distribu on of recruits In trawl samples
Spawning and recruitment seem to be concentrated in a few areas Does this mean they are different popula ons? Stock iden ty of horse mackerel in northern BCLME region
ü A total of 63 individuals from the whole T. trecae distribution and 82 of T. capensis were used for DNA isolation, purification and sequencing;
ü The total DNA isolation and was performed using kit GE (GE Healthcare, Brazil);
ü Cytochrome b from mitochondrial DNA was amplified using the primers: L-14841 5’AAAAAGCTTCCATCCAACATCTCAGCATGATGAAA 3’ H-15149 3’AAACTGCAGCCCCTCAGAATGATATTTGTCCTCA 3’
Molecular Methodologies
ü Genetic variability was estimated using the following parameters: Nucleotide and haplotype diversities using DnaSP package.
ü Inter population variability was in silico evaluated using AMOVA implemented by Arlenquin version 3.5.1.2. Results: Trachurus trecae Genetic Variability
Characteris c North Center South Total The observed values of Sequence 25 22 16 63 diversity nucleotide are Number bellow of variation reviewed for marine fish Total sites 350 350 350 that varies 0,8-3,20%.
Total number 10 12 9 22 of nuta on
Diversity 0,00448 0,00549 0,00557 0,00501 nucleo de (±SD) (±0,001) (±0,0010) (±0,001) (±0,009) Diversity haplotype for Number of 10 10 8 23 northern and central haplotype region are bellow of the Diversity 0,690 0,662 0,800 0,707 variation demonstrated haplotype (±SD) (±0,102) (±0,116) (±0,0920 (±0,065) for marine fish (h=0,7-1,0). For the southern region is D Tajima -1.70678* -1.82659* -1.50615 NS 2,16013* within the variation.
*significative values (p<0,05); NS no significative value(p>0,05) Results: Trachurus trecae Genetic Variability
ü According to the classification Grant e Bowen, 1998 Trachurus trecae seems to be a population with high diversity haplotypes and low diversity nucleotide is characteristic for population over exploited. For stable population both diversity haplotypes and nucleotide are high.
ü The effective number of inbreeding females (Nef) calculated from the ΘS indicates 371.000 female. The effective population size is always considerably smaller than census size.
Frequency of haplotype of Cytochrome b Trachurus trecae haplotype N North (%) Center (%) South(%) Hap_1 34 41 38 21 Hap_2 1 100 0 0 Hap_3 4 25 0 75 ü Only the haplotype number one Hap_4 1 100 0 0 is present in the three Hap_5 2 100 0 0 populations; Hap_6 3 66 34 0 Hap_7 1 100 0 0 ü Haplotype 3 is present in the Hap_8 1 100 0 0 north and south population; Hap_9 2 50 50 0 Hap_10 1 100 0 0 Hap_11 1 0 100 0 ü haplotype 6 and 9 are present in Hap_12 1 0 100 0 the north e center; Hap_13 1 0 100 0 Hap_14 1 0 100 0 ü The presence of several unique Hap_15 1 0 100 0 haplotype can be an indication Hap_16 1 0 100 0 that the abundance of Hap_17 1 0 100 0 population is fluctuating leading Hap_18 1 0 0 100 Hap_19 1 0 0 100 probably the accumulation of Hap_20 1 0 0 100 new mutation. Hap_21 1 0 0 100 Hap_22 1 0 0 100 Hap_23 1 0 0 100 Gene c structure of popula ons Trachurus trecae
Source varia on Variance % Φ P- componen variance Sta s cs value ts ü High genetic variability is found Inter- 0.00069 0.10 0.00096 >0,05 within each population; popula ons ü No genetic differentiation is Intra- 0.71613 99.90 >0,05 found between population. popula on
The lack of genetic differentiation can be attributed to high level of genetic flow characteristic for species with high capacity of dispersion as horse mackerel. Results: Trachurus capensis Genetic Variability
Characteris c Angola Namíbia Total
Sequence Number 29 53 82 Total sites 350 350 350
Total number of 14 23 30 nuta on Diversity 0,00872 0,00838 0,00067 nucleo de Number of 8 21 27 haplotype Diversity 0,8867 0,96807 0,94640 haplotype D Tajima -1,27328 * 1,33640 * 1,9906 * The observed values of haplotype and nucleotide diversity are within the variation demonstrated in reviews of the mitochondrial DNA of marine teleost fish (h=0,7-1,0 and π = 0.8 to 3.20%). Frequency of haplotype of Cytochrome b 3 haplotype N Angola Namibia Trachurus capensis Hap_1 19 52 48 Hap_2 38 63 37 Hap_3 1 100 0 Hap_4 1 100 0 Hap_5 1 100 0 Hap_6 1 100 0 Hap_7 1 100 0 Hap_8 1 100 0 Hap_9 1 100 0 ü Only two haplotypes are present in the two Hap_10 1 100 0 populations the others are unique to each Hap_11 1 100 0 the population; Hap_12 1 100 0 Hap_13 1 0 100 ü The presence of several unique haplotype Hap_14 1 0 100 Hap_15 1 0 100 can be an indication that the abundance of Hap_16 1 0 100 population is fluctuating leading probably the Hap_17 1 0 100 accumulation of new mutations. Hap_18 1 0 100 Hap_19 1 100 0 Hap_20 1 100 0 Hap_21 1 100 0 Hap_22 1 100 0 Hap_23 1 100 0 Hap_24 1 100 0 Hap_25 1 100 0 Hap_26 1 100 0 Hap_27 1 100 0 Gene c structure of popula ons Trachurus capensis
Source varia on Variance % Φ P-value components variance Sta s cs
Inter-popula ons -0,00246 -0,67 -0,0067 >0,05
Intra- popula ons 0,36955 100,67 >0,05
ü A large genetic variation is found within each population, in this case, Angola and Namibia ;
ü No genetic differentiation was found among populations. Final Remarks
ü According to Sardinha and Naeval (2002) studies with using isozymes was suggested the existence of two genetic groups on the Angola coast, one in tropical waters and another group in the south. However, the present study based on a different molecular marker did not show genetic differentiation among populations of T. trecae;
ü The genetic variability is within the range for fish marine species, there was no signal for decrease due to fisheries activity , at least using the Cytochrome b;
ü For T. capensis, the analysis showed no difference among populations caught in Angola and Namibia, suggesting that no oceanographic barriers exist that prevent gene flow between stocks captured in Angola and Namibia;
ü Due to the economic importance of T. tracea and T. capensis for fisheries along the Angola and Namibia coast, it is pivotal to develop other more polymorphic molecular markers, such as Microsatellites, specific for the species to further genetic monitoring of Trachurus populations for their sustainable use.