Can small pelagic fish landings be used as predictors of high-frequency oceanographic fluctuations in the 1–2 El Niño region?

Abstract

Abstract. A group of small pelagic fish captured between 1981 and 2012 within El Niño area 1–2 by the Ecuadorian fleet was correlated with the oceanographic Multivariate ENSO Index (MEI), and the Oceanographic El Niño Index (ONI) referred to El Niño region 3–4. For the period 1981–2012, total landings correlated poorly with the indexes, but during 2000–2012 (cold PDO) they proved to have a 14–29 % association with both indexes; the negative slope of the curves suggested higher landing during cold events (La Niña) and also indicated a tendency to decrease at extreme values ( > 0.5 and < −1.0). Round herring (Etrumeus teres) fourth-quarter (Q4) landings were related to the MEI in a nonlinear analysis by up to 80 %. During moderate or strong La Niña events landings noticeably increased. Bullet tuna (Auxis spp.) catches showed a negative gradient from cold to warm episodes with an R2 of 0.149. For Chilean jack mackerel (Trachurus murphyi) irregular landings between 2003 and 2007 were observed and were poorly correlated (R2 < 0.1) with ONI or MEI. Anchovy (Engraulis ringens) captured in Ecuadorian waters since 2000 had an R2 of 0.302 and 0.156 for MEI and ONI, respectively, but showed a higher correlation with the cold Pacific Decadal Oscillation (PDO). South American pilchard (Sardinops sagax) was higher than −0.5 for the ONI and MEI, and landings dramatically decreased; however, Q4 landings correlated with ONI and MEI, with R2 of 0.109 and 0.225, respectively (n = 3). Linear correlation of Q4 indexes against the following year's Q1 landings had a linkage of up to 22 %; this species could therefore be considered a predictor of El Niño. Chub mackerel (Scomber japonicus) landings did not have a significant linear correlation with the indexes for 1981–2012 and therefore could not be considered a valid predictor. Chuhueco (Cetengraulis mysticetus) is a local species with high landings during El Niño years and, conversely, remarkably low landings during La Niña years. Additionally, chuhueco availability and landings were negatively affected by cold PDOs. Pacific thread herring (Opisthonema spp.) showed a 24 and 36 % relationship between landings (Q1) and the MEI and ONI (Q4). Therefore, results suggest that the South American pilchard and Pacific thread herring could be considered good species to use as predictors of El Niño in region 1–2 (Ecuador), especially when average Q4 MEI ∕ ONI is used against the next trimester Q1 landing. All species were prone to lower landings and/or fishing availability during strong–extreme events (ONI/MEI, > 1.0 and < −1.0), and were also shown to be affected by the PDO. In the long term, landings decreased under warm PDO and vice versa, and therefore PDO fluctuations could be used to help manage these fisheries and to help the industry in long-term planning.

Relationships between tuna catch and variable frequency oceanographic conditions

“…In terms of a larger time scale index, such as the PDO, there is uncountable evidence that tuna fish biomass is at higher levels when the PDO is on cold phase (2000-2030). Ormaza-González et al (2016) have found the length and weight of Opisthonema spp (a type of sardine fish called "pinchagua") have a higher linear correlation up to 40 % to MEI and ONI indexes when data for the fourth quarter of the year was analyzed in time series 2000-2012 of these indexes. Similar outcomes where found when using small pelagic fish correlated to cold phase PDO (Ormaza-González et al, 2016).…”

“…Ormaza-González et al (2016) have found the length and weight of Opisthonema spp (a type of sardine fish called "pinchagua") have a higher linear correlation up to 40 % to MEI and ONI indexes when data for the fourth quarter of the year was analyzed in time series 2000-2012 of these indexes. Similar outcomes where found when using small pelagic fish correlated to cold phase PDO (Ormaza-González et al, 2016). The analysis of the CPUE suggests that fishermen and managers would expect higher CPUE on FADs around 20 mt set −1 when indexes are below -0.5.…”

“…The El Niño event increases sea water column and surface temperatures (leading to thermal anomalies as high as 6 • C; surface temperature > 27 • C, e.g. Trenberth, 1997), lowers salinity, from 35 down to 32 (D'Croz et al, 1991), leads to much lower nutrients and primary production productivity (Chavez et al, 2003), which in turn affects higher trophic levels, bringing positive and negative impacts on fisheries around Ecuador and Peru (Ormaza-González, 2008, 2009a, b, 2010a, b, 2011, 2012aKimura et al, 2001;Chávez et al, 2003;Ballón et al, 2008;Ormaza-González et al, 2016). Regarding the Pacific Interdecadal Oscillation (PDO), which was initially reported and named by Mantua et al (1997) in a paper about Alaskan Salmon (Oncorhynchus sp); this oscillation has been overlooked but a more recent summarizing paper gives good insights into the PDO (Mantua and Hare, 2002) and how this low frequency variation affects long term distribution trends of fisheries.…”

Overfishing and Climate Drives Changes in Biology and Recruitment of the Indian Oil Sardine Sardinella longiceps in Southeastern Arabian Sea

“…Explicably, the oil sardine catch and catch rates were negatively correlated with MEI and the relative importance model showed that MEI was the most important parameter explaining the variance (33%), thus indicating that the El Niño had negatively affected the sardine stock and its fisheries. In the round herring (Etrumeus teres) fishery in Ecuador, landings were related to the MEI in a nonlinear analysis by up to 80% (Ormaza-González et al, 2016). Among the different factors affecting spawning and recruitment of anchoveta populations, El Niño has been reported as the most striking (Checkley et al, 2009).…”

Coastal El Niño 2017 or Simply: The Carnival Coastal Warming Event?

“…Environmental impact is huge in terms of diluvial rain episodes [3], release of gases to the atmosphere as their solubility decreases because the sea surface temperature (SST) increases nutrient depletion [4] and reduction of photosynthesis [5]. The whole marine trophic chain is negatively affected: this include important fish stocks as small and big pelagic fish [6,7]. El Niño [8,9] is a relatively low frequency (inter-annual) and non-cycled oceanographicatmospheric coupled process whose definition is referred to the area Niño 3.4 ( Figure 1).…”