139
Fi s eco d o he whi e e ally (Pseudoca anx den ex) in he
Black Sea: a new occu ence om Bulga ian coas al wa e s
Radosla a Beko a1, Bogdan P odano 2
1 Depa men o Ma ine Biology and Ecology, Ins i u e o Oceanology – Bulga ian Academy o Sciences, Va na, Bulga ia
2 Coas al Zone Dynamics Depa men , Ins i u e o Oceanology – Bulga ian Academy o Sciences, Va na, Bulga ia
Co esponding au ho : Radosla a Beko a ( adosla [email p o ec ed])
Copy igh : ©
Radosla a Beko a & Bogdan P odano .
This is an open access a icle dis ibu ed unde
e ms o he C ea i e Commons A ibu ion
License (A ibu ion 4.0 In e na ional – CC BY 4.0).
Sho Communica ion
Abs ac
This s udy documen s he i s con i med eco d o he whi e e ally (Pseudoca anx
den ex) in he Black Sea. A specimen (354 mm TL and weigh 703 g) was eco ded
nea Va na, Bulga ia, on 24 July 2025. This obse a ion ep esen s he no he nmos
occu ence o he species along he wes e n Black Sea coas , ex ending i s known
dis ibu ion beyond he ansi ional zone o he Bospho us. The p esen eco d om
Va na Bay is loca ed app oxima ely 330 km no h o he p e ious no he nmos con-
i med occu ence in he Bospho us S ai , ma king a subs an ial no hwa d ex en-
sion along he wes e n Black Sea coas line. Iden i ica ion was based on mo pho-
logical and me is ic cha ac e is ics. Despi e abundan ben hic p ey in he a ea, he
specimen’s emp y s omach may indica e a ecen a i al o a ophic misma ch. The
inding suppo s he hypo hesis o me idionaliza ion and clima e-d i en ange shi s
o he mophilic ishes. Sea su ace empe a u es in he egion ha e inc eased by
~0.5 °C pe decade since he 1990s, c ea ing a o able condi ions o wa m-wa e
species. As a as -g owing, gene alis p eda o , P. den ex may al e ood web dy-
namics and in e ac wi h na i e species. This eco d unde sco es he need o sus-
ained ich hyo aunal moni o ing and u he esea ch on he ecological implica ions
o he mophilic newcome s in he Black Sea.
Key wo ds: Clima e-d i en dispe sal, ma ine biodi e si y moni o ing, me idionaliza ion,
ange expansion, he mophilic species, wes e n Black Sea
In oduc ion
The whi e e ally, Pseudoca anx den ex (Bloch & Schneide , 1801), is a he -
mophilic ca angid ish ha inhabi s ma ine and b ackish wa e s in opical
and sub opical egions ac oss all majo ocean basins. Howe e , i is also
occasionally ound in empe a e zones (F oese and Pauly 2023). The spe-
cies is ee -associa ed and ypically occu s a dep hs o 10–25 m, al hough
i has been eco ded down o 238 m.
The species exhibi s a b oad Indo-Paci ic dis ibu ion, including he
coas s o Sou h A ica, Japan, Aus alia, New Zealand, Hawaii, Lo d Howe
and No olk Islands, and New Caledonia. I is also p esen in he wes e n
A lan ic om No h Ca olina and Be muda o sou he n B azil and in he
Academic edi o : K emena S e ano a
Recei ed:
13 Augus 2025
Accep ed:
26 Oc obe 2025
Published:
21 No embe 2025
ZooBank: h ps://zoobank.
o g/35FF61AF-5F37-487C-82F2-
F8A9224AF6C6
Ci a ion: Beko a R, P odano B (2025)
Fi s eco d o he whi e e ally
(Pseudoca anx den ex) in he Black
Sea: a new occu ence om Bulga ian
coas al wa e s. Na u e Conse a ion
60: 139–149. h ps://doi.o g/10.3897/
na u econse a ion.60.168638
Na u e Conse a ion 60: 139–149 (2025)
DOI: 10.3897/na u econse a ion.60.168638
This a icle is pa o :
Black Sea ecosys em in he spo ligh
Edi ed by K emena S e ano a,
Snejana Monche a, E uğ Düzgüneş,
Lyubomi Dimi o
140
Na u e Conse a ion 60: 139–149 (2025), DOI: 10.3897/na u econse a ion.60.168638
Radosla a Beko a & Bogdan P odano : Whi e T e ally (Pseudoca anx den ex) in he Bulga ian Black Sea
eas e n A lan ic and adjacen seas, anging om he Medi e anean and he
Azo es o Madei a, he Cana y Islands, Cape Ve de, Ascension Island, and
S . Helena (F oese and Pauly 2023).
P. den ex is cha ac e ized by a usi o m, la e ally comp essed body, me allic
g eenish-blue do sally and sil e y whi e en ally, wi h a p ominen da k blo ch
on he ope culum and a yellow s ipe along he midline. Me is ic ea u es in-
clude 9 do sal spines, 25–26 do sal so ays, 3 anal spines, 21–22 anal so
ays, and 25 e eb ae (Smi h-Vaniz 1986; Kailola e al. 1993). The la e al line
bea s 57–78 scales on i s cu ed sec ion and 34–46 scu es pos e io ly (Nei a
e al. 1998). Adul s ypically inhabi coas al wa e s, bays, and es ua ies, o m-
ing schools nea he bo om o a ound ee s and ough subs a es, whe eas
ju eniles a e mo e common in shallowe es ua ine and shel habi a s (May and
Maxwell 1986; Kailola e al. 1993). Feeding s a egies include am- il e ing and
suc ion eeding on plank on and ben hic in e eb a es (Annala 1994; Sazima
1998). Rep oduc ion in ol es pelagic eggs (Smi h-Vaniz 1986).
The p esence o P. den ex has been well documen ed in he Medi e anean
Sea. In he wes e n basin, i was epo ed along he eas e n and sou he n Ad i-
a ic coas s by Pallao o and Ja das (1996) and Dulčić e al. (2003), and along
he I alian coas by Cos a (1991). Mo e ecen ly, Ti alongo e al. (2018) eco d-
ed he species on he sou heas e n coas o Sicily be ween 2013 and 2017.
Azzu o e al. (2013) no ed i s egula p esence in ish assemblages a ound
Lampedusa Island in he S ai o Sicily.
In he eas e n Medi e anean, he species has been epo ed in Sy ian
wa e s (Saad 2005), in he Le an ine Sea (Gücü and Bingel 1994), and o
he coas o No h Cyp us du ing 2015–2016 (Yalgın and Tü ke 2023). I
has also been obse ed along he Libyan coas line in he sou he n Medi e -
anean (Elba aasi e al. 2019).
In he Aegean Sea, Giakoumi and Kokko is (2013) documen ed he spe-
cies in he coas al wa e s o he Cyclades A chipelago du ing 2007–2008.
Mo e ex ensi e moni o ing by Tüney-Kızılkaya e al. (2020) con i med he
p esence o P. den ex a ound ish agg ega ion de ices (FADs) in Kuşadası
Bay, aquacul u e cage a eas in Güllük Bay, and ee habi a s in Göko a Bay
be ween 2009 and 2019.
This obse a ion cons i u es he i s con i med eco d o P. den ex in Bul-
ga ian Black Sea wa e s and ep esen s a signi ican no hwa d ex ension
o he species’ known dis ibu ion in o he Black Sea p ope . Ea lie in es-
iga ions on ich hyo auna and ish ap ca ches om he Bospho us egion
al eady indica ed he p esence o he mophilic Medi e anean elemen s in
he ansi ional wa e s be ween he Ma ma a and he Black Sea (Aydınyazıcı
and Öke 1960). The p e ious no he nmos eco d was epo ed om he
Beykoz coas in he Bospho us S ai (Keskin 2023), in he ansi ional zone
o he Medi e anean–Black Sea in e ace.
The aim o his epo is o documen and desc ibe he i s con i med
occu ence o P. den ex in he ully ma ine coas al wa e s o he Black Sea,
based on a specimen cap u ed nea Va na, Bulga ia. Mo phological and
me is ic ai s a e analyzed o con i m he species iden i ica ion, and po-
en ial clima ic and ecological d i e s o his occu ence a e discussed in
he con ex o ecen wa ming ends and ange expansions o he mophilic
ishes in he egion.
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Radosla a Beko a & Bogdan P odano : Whi e T e ally (Pseudoca anx den ex) in he Bulga ian Black Sea
Ma e ials and me hods
On 24 July 2025, a ec ea ional di e used a spea gun o cap u e a specimen
o P. den ex in shallow coas al wa e s (dep h ~4.5 m) nea T aka a, Va na,
Bulga ia (43°13.04061'N, 27°58.63438'E) (Fig. 1A–B). The ish was pho o-
g aphed in si u and p ese ed on ice be o e being measu ed and weighed.
Six een mo phome ic cha ac e is ics we e measu ed ollowing Smi h-Va-
niz (1986) and a e lis ed in Table 1 and illus a ed in Fig. 3: (1) o al leng h,
(2) body dep h, (3) head leng h, (4) snou leng h, (5) o bi diame e , (6) uppe
jaw leng h, (7) lowe jaw leng h, (8) dis ance om snou ip o i s do sal in
Figu e 1. A. Loca ion o he i s con i med eco d o Pseudoca anx den ex in he Black
Sea; B. Loca ion o he eco d in he Bulga ian Black Sea coas al wa e s a he T aka a
locali y, Va na Bay ( ed poin ).
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Radosla a Beko a & Bogdan P odano : Whi e T e ally (Pseudoca anx den ex) in he Bulga ian Black Sea
o igin, (9) o second do sal in o igin, (10) o pec o al in inse ion, (11) o
pel ic in inse ion, (12) o anal in o igin, (13) pel ic in leng h, (14) pec o al
in leng h, (15) in e o bi al leng h, and (16) s anda d leng h. All measu e-
men s we e aken wi h a digi al calipe o he nea es 0.1 mm and exp essed
in cen ime e s. No me is ic ea u es we e eco ded.
Resul s
Based on body mo phology and colo a ion, he specimen was iden i ied as
Pseudoca anx den ex—a deep-bodied, la e ally comp essed ish wi h a me al-
lic bluish-g een do sal su ace, sil e y lanks, and a cha ac e is ic da k spo
on he ope culum. The specimen measu ed 354 mm in o al leng h, 285 mm in
s anda d leng h, and weighed 703 g. The species de e mina ion was con i med
using keys p o ided in egional ich hyological li e a u e and was consis en
wi h he desc ip ion in Keskin (2023). The p esen eco d om Va na Bay a
coo dina es 43°13.04061'N, 27°58.63438'E, a a dep h o ~4.5 m on a sandy
bo om, is loca ed ~330 km no h o he p e ious no he nmos con i med
occu ence o P. den ex in he Bospho us S ai (Keskin 2023), ep esen ing a
subs an ial no hwa d ex ension along he wes e n Black Sea coas line (Fig.
1). A e emo ing he s omach, i was ound o be emp y.
Table 1. Lis o mo phome ic cha ac e is ics measu ed om he specimen o Pseudoca anx den ex om Va na Bay,
Bulga ia, on 24 July 2025.
№Mo phome ic
cha ac e is ic Abb e . De ini ion ( om… o…) Leng h
(cm) % TL* % HL*
1 To al leng h TL Snou ip o caudal in ip 35.4 100.0 343.7
2Body dep h a he i s
do sal in o igin BD Maximum body dep h a D1 o igin 10.7 30.2 103.9
3 Head leng h HL Snou ip o pos e io ma gin o ope culum 10.3 29.1 100.0
4Snou o second
do sal in o igin S–D2 Snou ip o D2 o igin 16.6 46.9 161.2
5 Diame e o o bi ED Ho izon al eye diame e 1.8 5.1 17.5
6 Uppe jaw leng h UJL An e io ip o p emaxilla o pos e io end o maxilla 3.4 9.6 33.0
7 Lowe jaw leng h LJL An e io ip o den a y o pos e io end o mandible 7.7 21.8 74.8
8Snou o i s do sal
in o igin S–D1 Snou ip o D1 o igin 11.8 33.3 114.6
9 Snou leng h SnL Snou ip o an e io ma gin o o bi 3.9 11.0 37.9
10 Snou o pec o al in
inse ion S–P Snou ip o pec o al in inse ion 10.2 28.8 99.0
11 Snou o pel ic in
inse ion S–V Snou ip o pel ic in inse ion 10.6 29.9 102.9
12 Snou o anal in o igin S–A Snou ip o anal in o igin 19.1 54.0 185.4
13 Pel ic in leng h VFL Pel ic in base o ip 5.4 15.3 52.4
14 Pec o al in leng h PFL Pec o al in base o ip 11.0 31.1 106.8
15 In e o bi al leng h IO Sho es dis ance be ween he o bi s (do sal iew) 9.7 27.4 94.2
16 S anda d leng h SL Snou ip o caudal peduncle (end o hypu al pla e) 28.5 80.5 276.7
*TL – o al leng h; HL – head leng h. Pe cen ages a e calcula ed ela i e o TL o HL, depending on ana omical con ex .
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Radosla a Beko a & Bogdan P odano : Whi e T e ally (Pseudoca anx den ex) in he Bulga ian Black Sea
Figu e 3. Diag am o mo phome ic cha ac e is ic measu emen s aken om he specimen o Pseudoca anx den ex
om Va na Bay, Bulga ia, in 2025 (numbe s co espond o mo phome ic cha ac e is ics lis ed in Table 1).
Figu e 2. Pseudoca anx den ex and species om he amily Mugilidae (Mugil cephalus, Chelon au a us) om he T aka a
locali y, Va na Bay, Bulga ian Black Sea coas al wa e s.
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Radosla a Beko a & Bogdan P odano : Whi e T e ally (Pseudoca anx den ex) in he Bulga ian Black Sea
The diagnos ic ea u es o he examined specimen include an elonga e,
deep, and mode a ely comp essed body, an elonga ed snou , and a weakly de-
eloped adipose eyelid. The uppe jaw e mina es an e io o he eye ma gin.
The clei h um ma gin is smoo h and lacks papillae. Bo h jaws bea a single ow
o blun , conical ee h, and addi ional ee h a e p esen on he ongue. The spi-
nous po ion o he do sal in is ela i ely high, wi h he longes spine exceeding
he heigh o he so do sal lobe. The pec o al ins a e longe han he head,
and he en i e body is co e ed wi h small cycloid scales.
The body colo a ion is pale g eenish-blue do sally and sil e y en ally, wi h
a p ominen black spo on he pos e odo sal ma gin o he ope culum and a
yellow la e al s ipe ha b oadens pos e io ly. The bases o he so do sal and
anal ins exhibi yellow pigmen a ion, whe eas he caudal and so do sal ins
a e dusky yellow (Fig. 2). All mo phome ic and me is ic cha ac e is ics co e-
spond well wi h he desc ip ions p o ided by Smi h-Vaniz (1986). A key dis in-
guishing ai o P. den ex is he no ably long i s do sal spine, which exceeds
he heigh o he second do sal in lobe.
In addi ion o he mo phome ic measu emen s, he ollowing me is ic ea-
u es we e eco ded o he examined specimen: 9 do sal spines, 24 do sal
so ays, 3 anal spines, 20 anal so ays, and 25 e eb ae. The la e al line was
composed o 57 scales in he cu ed po ion and 39 pos e io scu es. These
alues all wi hin he ange epo ed o P. den ex in Medi e anean and A lan ic
popula ions (Smi h-Vaniz 1986; Nei a e al. 1998), u he suppo ing he axo-
nomic iden i ica ion o he specimen.
Discussion
The whi e e ally is a he mophilic ma ine ish belonging o he amily Ca an-
gidae. I is conside ed medium-sized, wi h a ypical s anda d leng h o a ound
400 mm (Smi h-Vaniz 1986). The maximum epo ed size in he Medi e anean
is 702 mm TL and 4,126 g (Tüney-Kızılkaya e al. 2020). Howe e , in o ma ion on
he Medi e anean popula ion o P. den ex emains limi ed, pa icula ly ega ding
i s dis ibu ion, eeding ecology, and ep oduc i e biology (Dulčić e al. 2003).
Acco ding o exis ing knowledge, P. den ex ypically inhabi s insho e wa e s,
wi h ju enile indi iduals o ming shoals and eeding p ima ily on ish la ae
and pos -la ae (Dulčić e al. 2003), as well as euphausiid la ae, amphipods,
copepods, and gas opods (Russell 1983). Adul indi iduals a e mo e soli a y
and eed on a b oad spec um o ben hic in e eb a es, including squid, cu -
le ish, in ish, c abs, sh imps, sea s a s, sea u chins, and bi al es (F oese and
Pauly 2023). Spawning gene ally occu s du ing he summe mon hs (Smi h-Va-
niz 1986). Ju eniles a e equen ly obse ed ailing behind species such as
mulle s and s iped seab eam in sandy-bo om habi a s, o en u ilizing loa ing
s uc u es o shel e om p eda o s. Bo h ne and hook ishe ies a ge he
species, and in he sou he n Medi e anean, i is also caugh using ish agg e-
ga ing de ices (FADs) (Deude o e al. 1999).
Ma ine biodi e si y, including ish species such as P. den ex, is inc eas-
ingly h ea ened by mul iple an h opogenic p essu es, including clima e
change, pollu ion, habi a deg ada ion, o e exploi a ion o esou ces, and
eu ophica ion. Among hese, global wa ming has eme ged as a key d i e
o dis ibu ional shi s. The mophilic and empe a e ish species wi h b oad
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Radosla a Beko a & Bogdan P odano : Whi e T e ally (Pseudoca anx den ex) in he Bulga ian Black Sea
he mal ole ance (~10 °C) a e excep ionally esponsi e o empe a u e
changes, enabling hem o main ain posi i e g ow h a es unde a ying
he mal condi ions (Pauly 2010; Cheung e al. 2013). The e m “me idional-
iza ion” has been used o desc ibe he no hwa d ange expansion o such
species in bo h he Medi e anean and adjacen egions (Bianchi and Mo i
1993). This la i udinal shi , d i en by ocean wa ming, is ecognized as one
o he mos obse able bio ic esponses o clima e change, pa icula ly in
ma ine ecosys ems (F ancou e al. 1994; Azzu o 2008). Fo ins ance, P.
den ex and o he he mophilic species such as Epinephelus ma gina us and
Ca anx c ysos ha e been documen ed o expand hei dis ibu ion no h-
wa ds in he Medi e anean Sea (Azzu o 2008).
In his con ex , Keskin (2023) epo ed he no he nmos known occu ence
o P. den ex wi hin he Medi e anean–Black Sea ansi ion zone, based on wo
indi iduals cap u ed nea he Beykoz coas in he Bospho us S ai (Fig. 1A).
Howe e , due o he ansi ional na u e o he Bospho us, which e ains cha ac-
e is ics mo e ypical o he Ma ma a Sea in e ms o oceanog aphy and auna,
ha eco d may no ep esen ac ual pene a ion in o he Black Sea basin. By
con as , he p esen inding om Va na Bay cons i u es he i s con i med oc-
cu ence o P. den ex in o sho e wa e s o he wes e n Black Sea, ma king he
species’ i s e i ied p esence in he Black Sea p ope and ex ending i s known
dis ibu ion ange (Fig. 1A–B).
The examined specimen had an emp y s omach, a inding o pa icula
in e es gi en he species’ ypical die o ben hic in e eb a es and small
deme sal ishes. Along he Bulga ian Black Sea coas , po en ial p ey o gan-
isms such as c us aceans (C angon c angon, Palaemon elegans), mollusks
(My ilus gallop o incialis, Donax unculus), and polychae es (Hedis e di-
e sicolo ) a e commonly ound in coas al ben hic habi a s. The absence
o ood in he s omach may indica e ei he ecen a i al and incomple e
acclima iza ion o local eeding g ounds o a b oade misma ch be ween
p e e ed p ey and he cu en s a e o he ben hic communi y—a scena io
po en ially linked o ongoing ecological shi s in he Black Sea. This obse -
a ion ex ends he known dis ibu ion o P. den ex by ~330 km no hwa ds
om he Bospho us S ai (Keskin 2023) in o he open coas al wa e s o he
wes e n Black Sea. Such a dis ance is no able o a single con i med eco d
and suppo s he iew ha he species is capable o subs an ial ange shi s
in esponse o changing en i onmen al condi ions.
Clima e change and he mophilic species
Recen analyses con i m a pe sis en ise in sea su ace empe a u e (SST) and
inc eased ma ine hea wa e (MHW) equency in he Black Sea (Ba e al. 2024).
These pa e ns a e consis en wi h clima e-induced ange expansions ob-
se ed o he mophilic species. No ably, he p esence o P. den ex in ully ma-
ine o sho e wa e s o he wes e n Black Sea coincides wi h a well-documen -
ed long- e m wa ming end in he egion. Sa elli e-based SST obse a ions o
he Black Sea show a s a is ically signi ican inc ease o app oxima ely 0.65 ±
0.07 °C pe decade om 1982 o 2020 (Mohamed e al. 2022), wi h pe sis en
wa ming ac oss seasons. This ise is accompanied by inc eased equency and
du a ion o MHWs, wi h obse ed ends o 1.4 addi ional e en s and 2.8 ex a
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Radosla a Beko a & Bogdan P odano : Whi e T e ally (Pseudoca anx den ex) in he Bulga ian Black Sea
MHW days pe decade. Such changes can enhance habi a sui abili y o he -
mophilic species and p omo e hei es ablishmen in p e iously coole egions.
These indings a e suppo ed by ope a ional da a om he Cope nicus Ma-
ine Se ice (CMS 2024), which es ima e a cumula i e SST end o app oxi-
ma ely 0.5 °C pe decade along he wes e n Black Sea coas since he ea ly
1990s. Toge he , hese lines o e idence indica e ha he mal condi ions in he
egion a e becoming inc easingly a o able o sub opical and empe a e-a in-
i y species such as P. den ex.
The new eco d, he e o e, p o ides u he e idence ha clima e-d i en he -
mal changes a e ac i ely eshaping species dis ibu ions in he Black Sea. The
likely clima e- ela ed a i al o P. den ex aligns wi h he obse ed me idionaliza-
ion p ocesses ac oss he Medi e anean–Pon ic egion.
This new eco d ein o ces conce ns ha clima e-induced shi s in species
dis ibu ions a e al eady a ec ing he ich hyo aunal composi ion o he Black
Sea. The a i al o he mophilic species such as P. den ex may lead o compe i-
ion wi h na i e axa, changes in ophic in e ac ions, and b oade al e a ions in
ecosys em unc ioning. The no hwa d expansion o he mophilic species such
as P. den ex may ha e cascading ecological implica ions, including compe i-
ion wi h na i e species and al e a ion o ood web dynamics. This highligh s
he impo ance o sus ained moni o ing and adap i e managemen s a egies
unde changing clima ic condi ions.
Conclusion
This epo documen s he i s con i med occu ence o P. den ex in he coas al
wa e s o he Black Sea, loca ed in Va na Bay, Bulga ia, ep esen ing a no able
ex ension o he species’ known ange wi hin he no heas e n Medi e anean–
Black Sea sys em. Compa ed o p e ious eco ds limi ed o he ansi ional
zone o he Bospho us (Keskin 2023), he inding nea Va na ma ks he no h-
e nmos con i med occu ence in ully ma ine o sho e condi ions o he wes -
e n Black Sea. This obse a ion aligns wi h a b oade egional wa ming end
and suppo s he hypo hesis o ongoing me idionaliza ion and clima e-d i en
ange expansion o he mophilic ma ine ishes.
The specimen’s mo phome ic and me is ic cha ac e is ics we e consis en
wi h known species desc ip ions, con i ming i s iden i y. The emp y s omach
is no able gi en he abundance o sui able ben hic p ey along he Bulga ian
coas . I sugges s a ecen a i al o a possible ophic misma ch, po en ially
e lec ing b oade ecological changes wi hin local ben hic communi ies.
Long- e m SST analyses o he Black Sea indica e a s a is ically sig-
ni ican wa ming o app oxima ely 0.6–0.65 °C pe decade since he ea ly
1980s (Mohamed e al. 2022), wi h addi ional con i ma ion om Cope ni-
cus Ma ine Se ice indica o s es ima ing ~0.5 °C pe decade in wes e n
coas al a eas (CMS 2024). This wa ming is also associa ed wi h inc easing
equency and du a ion o ma ine hea wa es, which a ec species mig a-
ion, es ablishmen , and ophic s abili y. The e o e, he p esence o P. den-
ex may e lec hese clima e-media ed habi a shi s.
Gi en accele a ing SST ends, his eco d p o ides u he e idence o
clima e-induced biogeog aphic shi s in he Black Sea. I highligh s he need
147
Na u e Conse a ion 60: 139–149 (2025), DOI: 10.3897/na u econse a ion.60.168638
Radosla a Beko a & Bogdan P odano : Whi e T e ally (Pseudoca anx den ex) in he Bulga ian Black Sea
o sys ema ic ich hyo aunal moni o ing o de ec eme ging dis ibu ional
pa e ns, assess ecological impac s on na i e communi ies, and in o m
adap i e conse a ion and ishe ies managemen in he ace o apidly
changing ma ine condi ions.
The en y o P. den ex in o he Black Sea is ecologically signi ican because i ep-
esen s he a i al o a mobile, oppo unis ic p eda o capable o exploi ing di e se
p ey esou ces and occupying mid- o uppe ophic le els. As a as -g owing and
gene alis species, P. den ex may in luence na i e ood webs h ough p eda ion,
compe i ion, o indi ec ecological in e ac ions. I s success ul es ablishmen unde
wa ming condi ions could signal b oade unc ional changes wi hin he Black Sea
ecosys em, especially i o he he mophilic species ollow simila ajec o ies (Rus-
sell 1983; Azzu o 2008; Cheung e al. 2013; F oese and Pauly 2023).
Acknowledgemen s
The au ho s exp ess hei g a i ude o Nikolay S e ano o cap u ing he spec-
imen and o D agomi Ene o acili a ing he connec ion.
Addi ional in o ma ion
Con lic o in e es
The au ho s ha e decla ed ha no compe ing in e es s exis .
E hical s a emen
No e hical s a emen was epo ed.
Use o AI
No use o AI was epo ed.
Funding
The publica ion was inancially suppo ed by he p ojec “Raising public awa eness,
mapping and educing an h opogenic was e o he p o ec ion o he Bulga ian Black
Sea beaches and dunes,” G an № А24-677, pa o he scien i ic esea ch p og am o
he DER TOURISTIK FOUNDATION, Ge many.
Au ho con ibu ions
Radosla a Beko a concei ed and designed he s udy, conduc ed he li e a u e e iew,
iden i ied species, pe o med mo phological and me is ic analyses, and p epa ed he
ini ial manusc ip d a . Bogdan P odano p ocessed he GIS da a, e ined he igu es,
and ca ied ou a c i ical e iew and e ision o he manusc ip . Bo h au ho s app o ed
he inal e sion o publica ion.
Au ho ORCIDs
Radosla a Beko a h ps://o cid.o g/0000-0002-9353-1956
Bogdan P odano h ps://o cid.o g/0000-0002-8118-3034
Da a a ailabili y
All o he da a ha suppo he indings o his s udy a e a ailable in he main ex .
