Latitudinal and bathymetric patterns in the distribution and abundance of mesopelagic fish in the Scotia Sea

first_imgMesopelagic fish are a key component of the pelagic ecosystem throughout the world’s oceans. Opening and closing nets were used to investigate patterns in the distribution and abundance of mesopelagic fish from the surface to 1000 m on a series of transects across the Scotia Sea from the ice-edge to the Antarctic Polar Front. A total of 141 non-target net hauls were undertaken during three cruises (Nov 2006, Jan 2008 and Mar 2009), with 7852 teleost fish captured, representing 43 species in 17 families. A further 1517 fish were caught in targeted net hauls. The dominant families were the Myctophidae (6961 specimens; 21 species) and Bathylagidae (1467 specimens; 4 species). Few fish were caught in the upper 400 m during daylight, which was attributed to a combination of net avoidance and diurnal vertical migration. Species composition was linked to depth and location and was closely associated with oceanographic features. Diversity was lowest in cold water at the most southerly stations, which were dominated by Electrona antarctica, Gymnoscopelus braueri and Bathylagus antarcticus. Further north, diversity increased with the addition of species such as Krefftichthys anderssoni, Protomyctophum bolini and Electrona carlsbergi. The depth integrated biomass of myctophids was similar across the latitudinal transect and produced an estimate of 4.5 million tonnes in the Scotia Sea. Bathylagids were patchily distributed, but were abundant in the lower mesopelagic zone (>400 m) and are potentially significant zooplankton consumers. Given the biomass of the myctophids and bathylagids coupled with the vertical migrations of many species, these fish are likely to play a significant role in carbon export from the surface waters to the deep ocean.last_img read more

Mikel Arteta sets challenge to Bukayo Saka and Kieran Tierney over Arsenal left-back spot

first_imgMikel Arteta sets challenge to Bukayo Saka and Kieran Tierney over Arsenal left-back spot Metro Sport ReporterFriday 6 Mar 2020 5:14 pmShare this article via facebookShare this article via twitterShare this article via messengerShare this with Share this article via emailShare this article via flipboardCopy link4.6kShares Saka has made the left-back spot his own (Picture: Getty Images)Arsenal boss Mikel Arteta has pitted Bukayo Saka and Kieran Tierney against each other for the mantle of the club’s first choice left-back. Teenager Saka has nailed down the position in the absence of Tierney and Sead Kolasinac, who have both spent extended periods on the sidelines. Scotland international Tierney has only just returned to first-team training, after being ruled out with a shoulder injury in December. And Arteta is expecting the pair to battle it out for their place between now and the end of the season, saying: ‘They [Saka and Tierney] have to compete, they have to challenge each other and improve.AdvertisementAdvertisementADVERTISEMENT‘Whoever is best will be in the position, which is a really good thing for the team.’ Advertisement Advertisement Tierney is back in training after months out from dislocating his shoulder (Picture: Getty Images)Saka’s standout performances have drawn interest from the likes of Manchester United and Liverpool, who are both monitoring his contract situation closely. The England youth international’s current deal at the Emirates Stadium expires in less than 18 months, with negotiations over an extension still ongoing.The natural winger has provided 10 assists in his debut season, and will be difficult to dislodge from the starting XI.More: Arsenal FCArsenal flop Denis Suarez delivers verdict on Thomas Partey and Lucas Torreira movesThomas Partey debut? Ian Wright picks his Arsenal starting XI vs Manchester CityArsene Wenger explains why Mikel Arteta is ‘lucky’ to be managing ArsenalWhen asked about Tierney’s fitness before Saturday’s game against West Ham, Arteta added: ‘He’s done two or three complete sessions now.‘He’s feeling more and more confident with contact around him and hopefully he will join in the [matchday] squad soon.’Follow Metro Sport across our social channels, on Facebook, Twitter and Instagram.For more stories like this, check our sport page.MORE: Charlie Nicholas names the five most exciting youngsters at ArsenalMORE: Mikel Arteta orders transfer clear-out of Arsenal stars to facilitate new signings Commentlast_img read more

O’Neill not pressuring Grealish

first_img As long as Grealish remains uncapped by Ireland, there is the possibility that Hodgson could persuade him that his international future could lie with England, although O’Neill was not to be drawn on the subject. He said: “I’ve no idea. I think you’ll have to ask Roy. “Seriously, I don’t want to sound as if England are miles better than us, but I think it would be difficult to get into the England squad just at this moment.” If Grealish’s absence was the main topic for discussion from the squad announcement in Dublin, there were notable first inclusions for Brentford midfielder Alan Judge and Aberdeen striker Adam Rooney in a provisional 33-man party. There were places too for veterans John O’Shea and Robbie Keane, despite both currently being on the injured list at their respective clubs, with the Sunderland defender battling to shake off a rib problem and the LA Galaxy striker nursing a groin strain. However, O’Neill is confident both will be able to meet up on or around June 1, with his 65-goal striker having confirmed that he will be heading across the Atlantic once again. Asked about Keane’s fitness, the Derryman said: “He’s okay, he’s all right. He’s just texted a message through to say he’s okay.” Squad: David Forde (Millwall), Shay Given (Aston Villa), Keiren Westwood (Sheffield Wednesday), Darren Randolph (Birmingham),; Richard Keogh (Derby), Marc Wilson (Stoke), Seamus Coleman (Everton), Cyrus Christie (Derby), John O’Shea (Sunderland), Alex Pearce (Reading), Paul McShane (Hull), Stephen Ward (Burnley); James McCarthy (Everton), Jeff Hendrick (Derby), Harry Arter (Bournemouth), Glenn Whelan (Stoke), Aiden McGeady (Everton), James McClean (Wigan), Alan Judge (Brentford), Robbie Brady (Hull), Anthony Pilkington (Cardiff), Stephen Quinn, David Meyler (both Hull), Wes Hoolahan (Norwich); Robbie Keane (LA Galaxy), Shane Long (Southampton), Daryl Murphy (Ipswich), Jon Walters (Stoke), Kevin Doyle (Colorado Rapids), Anthony Stokes (Celtic), David McGoldrick (Ipswich), Adam Rooney (Aberdeen), Simon Cox (Reading). O’Neill initially accepted that stance, but decided to test the water with the youngster having forced his way into the first-team picture at Villa in recent weeks to rave reviews. He said: “I don’t think it’s an attempt to pre-empt anything. I think Jack had mentioned before, in fairness to him, that he didn’t want to make a decision at that time. Again, my point was that then, since he wasn’t a regular member of the side, it seemed less important at that stage. “I still think really, regardless of that, that bringing him into the squad for a week’s training and seeing how he gets on, obviously in an attempt to try to see that the FAI would actually look after him…I think they have done at every level, believe it or not. “There might have been something in that, but at the end of the day he has done well enough at Aston Villa to be thought of as a proper senior player. “I spoke to both Jack and his father and I think Jack just didn’t want to make his mind up at this stage. He wanted to complete the season at Aston Villa – there are some important games for them coming up – and he wants to make his decision at some time in the future.” O’Neill admitted his disappointment at Grealish’s decision, but did not consider it a snub. He said: “No. I don’t take it personally. I think Jack is pretty firm in what he wants to do and that’s fine. “He has been doing very well recently and it would have been nice, but that’s Jack’s decision. I spoke to the father and said I would like to have brought him into it, but of course you don’t want to force someone who might not want to make that decision just at this moment.” O’Neill revealed on Tuesday that the Birmingham-born 19-year-old, who is currently at the centre of a tug-of-war between Ireland and England, has rejected the chance to join up with the squad for next month’s friendly against Roy Hodgson’s side and the Euro 2016 qualifier clash with Scotland. However, despite months of patient pursuit, during which assistant manager Roy Keane also went to work on the teenager, Grealish is sticking to his guns after revealing earlier in the year that he would make his decision at the start of next season. Press Association Martin O’Neill has insisted he did not attempt to force Aston Villa starlet Jack Grealish’s hand by offering him the chance to commit to the Republic of Ireland once again. last_img read more