Table 1. Significance of traits at the level of species, community, ecosystem functioning and anthropogenic effects.
| Significance or implications at the level of: | |||||
|---|---|---|---|---|---|
| a/a | Trait (example) | Population/species | Community | Ecosystem | Anthropogenic effects |
| 1 | Longevity (5 years) | Longer lifespan increases reproductive success over time (Beauchard et al., 2017) | Higher longevity renders individual more important both as prey and as a predator as more instances of predation | Longevity is related with natural mortality and thus with energy transfer in the ecosystem (Charnov, Gislason & Pope, 2013) | Longevity and age at maturity are related with the ability to recover from anthropogenic disturbance (Kaiser et al., 2006; Rijnsdorp et al., 2016) |
| May indicate population stability over time and potential of the various life stages to disperse (Costello et al., 2015) | |||||
| 2 | Age-at-maturity (30% of lifespan) | Early maturity may increase resilience in unfavourable environmental conditions (Bamber, 1995) | NR | Ecosystem characteristics (e.g., productivity) may enhance or delay maturation | Longevity and age at maturity are related with the ability to recover from anthropogenic disturbance (Rijnsdorp et al., 2016) |
| Associated with cessation of growth (Jonsson & Jonsson, 1993) | Early maturation may increase resilience in high exploitation rates. Maturity significant for fisheries management (measures planned to ensure population part achieves sexual maturity) | ||||
| 3 | Fecundity (5–10 eggs) | If low should ensure offspring survival-population fitness, as energy allocated to survival of offspring or fecundity (r/K-selection strategy) (Pianka, 1970) | High fecundity means higher abundance of young “defenceless” stages (eggs, larvae) that are possible prey for other populations, but higher inter-specific competition later on (Bamber, 1995) | As it provides easy-to-capture and rich in energy prey (compared to adult prey) may influence energy flow rates | Together with mortality until recruitment may affect stock size which is very relevant for fisheries (Jennings, Kaiser & Reynolds, 2001) |
| 4 | Hermaphroditism (gonochoristic) | Sexual maturity of the second (in succession) sex must be achieved through survival to guarantee successful spawning and recruitment | NR | NR | As both sex ratio and gear selectivity change with size, exploitation of one size part of the population may affect sex ratio and possibly reproductive success. |
| Size is important in determining male reproductive success (Wooton, 1999) | |||||
| 5 | Maximum length (20 cm) | Related to individual biomass, food web position, abundance, metabolic rates, and dispersal (Costello et al., 2015) | As in the marine ecosystem there is an ”eat what is smaller” pattern, there has to be some variability in species sizes to support a community (Giacomini, Shuter & Baum, 2016; Kerr & Dickie, 2001) | Related to energy flow in the ecosystem (because of association with trophic level/diet) and resulting food webs (Gerlach, Hahn & Schrage, 1985; Jennings, 2005) | Relevant for fisheries (with regard to body shape) for selectivity (Jennings, Kaiser & Reynolds, 2001) |
| 6 | Body form (flat) | Related to position in the water column/habitat, diet/potential prey, activity (Henseler et al., 2019; Wooton, 1999) | Because of association with habitat, specific communities may have higher frequencies of some body forms | NR | Related to the way fishing gear may affect selectivity (together with size) (Jennings, Kaiser & Reynolds, 2001) |
| 7 | Optimal depth (0–50 m) | Physical factor determining potential species habitat (Costello et al., 2015) | Depth is a major factor shaping marine communities (Pereira et al., 2018; Vega-Cendejas & De Santillana, 2019) | Depth may affect productivity and energy flow as e.g., below the euphotic zone the lack of primary production modifies trophic links. Also effects of elements like critical depth or seagrass bed distribution (Kaiser et al., 2006) | Different gears and fishing sectors are often operating in different depths resulting in different communities prone to exploitation and resulting catch composition (Tserpes, Tzanatos & Peristeraki, 2011) |
| 8 | Optimal temperature (25–30 °C) | Defines optimal temperature conditions for population fitness. May affect movement between water masses (behavioural thermoregulation) and thus abundance and distribution (Moyle & Cech Jr, 2004) | Due to climate change can shift to dominance of more thermophilic species (Lejeusne et al., 2010) | NR | More thermophilic species may appear more frequently in the catches ((Cheung, Watson & Pauly, 2013); Vasilakopoulos et al., 2017) |
| 9 | Habitat type (benthic) | Populations are closely associated to pelagic or benthic habitat or migrate between them (Henseler et al., 2019; Wooton, 1999) | Specific habitats are characterised by specific communities (Ballesteros, 2006; Kalogirou et al., 2010) | Effect of seabed type on ecosystem functioning expected to be significant as both are related to biodiversity and its attributes (Loreau et al., 2001) | Has implications for target species abundance and bycatch (thus fishing gear use) (Tzanatos et al., 2006) |
| 10 | Distribution (tropical) | Related to proximity to the geographic distribution of the area examined (if e.g., through Gibraltar or Suez in the Med) and could be associated to favourable environmental conditions (Coll et al., 2010) | Species of alien distribution (invasive) species may dominate the community through colonisation of empty niches/lack of “natural enemies” (Givan et al., 2017) | NR | Climate change or other environmental changes may be forcing changes in distribution paterns (Galil, 2007, Occhipinti-Ambrogi & Savini, 2003) |
| 11 | Sea bed type (hard) | Physical factor determining potential species habitat (Costello et al., 2015) | Specific habitats host and are characterized by specific communities (Ballesteros, 2006; Kalogirou et al., 2010) | Effect of seabed type on ecosystem functioning expected to be significant as both are related to biodiversity and its attributes (Loreau et al., 2001; Solan, Aspden & Paterson, 2012) | Has implications for target species abundance and bycatch (thus gear use) (Tzanatos et al., 2006) |
| 12 | Spawning habitat (pelagic) | Spawning habitat determines the nature and intensity of hazards encountered by eggs and larvae (Leis, 2006; Wooton, 1999) | May determine seasonal communities as a result of spawning seasonality and also of populations feeding on eggs and juveniles | If spawning habitat different from adult stage habitat may be relevant to benthopelagic coupling (Leis, 2006; Secor, 2015) | May create aggregations prone to fisheries (Erisman et al., 2017) |
| 13 | Temperature range (eurythermal) | May increase population resilience to abrupt temperature changes or ability to change environment | Eurythermal species may dominate community under climate change/frequent weather changes | NR | May increase population resilience to climate change, invasion rates and appearance in the fisheries catch |
| Eurythermal species may be favoured in thermal pollution sites (Bamber, 1995) | |||||
| 14 | Salinity range (stenohaline) | May be related to population ability to approach/enter productive habitats like estuaries & lagoons (Moyle & Cech Jr, 2004) | Shapes communities of brackish waters, e.g., along salinity gradients (Henriques et al., 2017; McLusky & Elliott, 2007; Pasquaud et al., 2015) | Relevant to matter & energy transfer between the ocean and brackish waters through euryhaline species (Martino & Able, 2003) | Shapes the resources exploited by fisheries in brackish environments (e.g., lagoon fisheries) (Katselis et al., 2003) |
| 15 | Depth range (eurybathic) | Eurybathic species have more potential habitat and might be more resilient to habitat loss (Costello et al., 2015) | Communities dominated by eurybathic species may be more resilient to environmental changes and disturbance | Eurybathic species may transfer energy through depth zones and contribute to benthopelagic coupling | More eurybathic species may be more resilient to habitat degradation by fisheries or other anthropogenic effects |
| 16 | Seasonal migrations (migratory) | Can change the population ecological status, may lead to a seasonal (periodic) life strategy and shape seasonal energy needs (Secor, 2015; Winemiller & Rose, 1992) | Community will change seasonally, qualitatively and quantitatively (Park et al., 2019) | Can have impact on energy flow, creating seasonal dynamics (Secor, 2015) | Many fisheries are based on seasonal migrations for fishing grounds or even operation of specific gears (e.g., lagoon fisheries) (Katselis et al., 2003) |
| 17 | Trophic level (3.5–4.2) | Derived from the type and frequency of trophic objects in its diet (Costello et al., 2015) | Influence on other species abundance and community structure and dynamics (Costello et al., 2015) | May alter nutrient cycling in the ecosystem (Beauchard et al., 2017) | Depending on exploitation removing part of the trophic network may result in fishing down the food web (Pauly et al., 1998) |
| 18 | Diet (zooplankton) | Determines food web position (Costello et al., 2015) | Influence on other species abundance and community structure and dynamics (Costello et al., 2015) | May alter nutrient cycling in the ecosystem (Beauchard et al., 2017) | Relevant to fishing gear mode of operation exploiting diet (hook and line gears e.g., longlines) and associated target species & catch composition |
| 19 | Spawning period (spring) | Shapes the period that the population must feed to prepare spawning and non-feeding period. May be associated with “weak” period (bad condition) after spawning (Dutil, 1986; Engelhard & Heino, 2005) | May shape feeding interactions and trophic links within the community seasonally, both as a result of preying on eggs and larvae and, secondarily, because of the seasonal pattern of recruitment (Edworthy & Strydom, 2016) | Is affected by suitability of the environmental conditions for eggs & larvae. Is affected by energy supply (low energy may result in delay or skipping spawning). As the spawning period generates eggs and larvae it provides potential prey (Rideout, Morgan & Lilly, 2006; Wooton, 1999) | Seasonality of fisheries may lead to unsuccessful spawning and result in few individuals recruited |
| 20 | Feeding type (plankton) | Related to the diet and the trophic level through the relative size and mobility of the prey in comparison to the predator (Costello et al., 2015) | By shaping diet can affect the community composition | Related to prey community composition and lower trophic level succession patterns (Mariani et al., 2013) | Relevant to fishing gear mode of operation exploiting feeding behaviour (hook and line gears e.g., trolling lines, longlines) and associated target species & catch composition (Jennings, Kaiser & Reynolds, 2001) |
| 21 | Sociability (schools) | Benefits like predation avoidance, food location and foraging strategy, improvement of reproductive success (Pitcher & Parrish, 1993; Wooton, 1999; Krause & Ruxton, 2002) | Schooling important in shaping communities regarding hydrodynamic characteristics (Floeter et al., 2007) | Schooling/pelagic fish may colonise new habitats (e.g., reefs) more easily (Paxton et al., 2018) | Relevant to fishing gear mode of operation exploiting gregarious fish behaviour (e.g., purse seines) and associated target species & catch composition (Jennings, Kaiser & Reynolds, 2001) |
| Costs like competition for food or mate, predator attraction, disease transmission (Côté & Poulin, 1995; Krause & Godin, 1995) | Schooling/pelagic fish may colonise new artificial habitats (e.g., reefs) more easily (Paxton et al., 2018) | ||||
| 22 | Exposure (cryptic-temporarily) | Population must balance ability to graze/predate and predation avoidance | Depending on conditions (e.g., habitat type) cryptic species may dominate communities (Schrandt et al., 2018) | NR | NR |
| Population (especially cryptic) may have developed diel activity rhythms (Matheson et al., 2017) | Level of exposure and cryptic behaviour relevant to differences in diel community composition (Matheson et al., 2017), | ||||
| 23 | Mobility (high) | Indicates a dispersal potential and a more or less mobile lifestyle (Costello et al., 2015) | Might differentiate pelagic (more motile) from benthic (more static) communities | May be relevant to transfer of energy between ecosystems or benthopelagic coupling | Relevant to fishing gear mode of operation exploiting fish motility behaviour (e.g., nets) and associated target species & catch composition (Ferno & Olsen, 1994; Jennings, Kaiser & Reynolds, 2001) |
Notes.
NR, Not relevant. References with explanation/examples are indicated with numbers corresponding to in-text citations following and are listed in detail in the Reference list.